UNIVERSITY   OF  CALIFORNIA    PUBLICATIONS. 

COLLEGE  OF  AGRICULTURE. 

AGRICULTURAL  EXPERIMENT  STATION, 

BERKELEY,  CALIFORNIA. 


INSECTS  INJURIOUS  TO  THE  VINE 
IN  CALIFORNIA. 


Phylloxera  {Phylloxera  vastatrix  Plan.).  Flea  Beetles  (Haltica  sps.). 

Grape  Leaf  Hopper  (Typhloeyba  comes  Say).  Grape  Leaf-folder  (Desrnia  funeralis  Hubn.). 

Imported  Grape  Root  Worm  (Adoxus  vitis  Leaf  Chafers. 

Fourcroy).  Wire  Worms. 

Hawk  Moth  Larvte.  Erinose. 

Grasshoppers.  Nematode  Root  Gall)  Heterodera  radicola 

Cut  Worms  and  Army  Worms.  (Greef)  Mull.). 


By  H.  J.  QUAYLE. 


BULLETIN    No.    192 

(Berkeley,  Cal.,  October,  1907.) 


SACRAMENTO: 
w.  w.  shannon,     :     :     :     :     superintendent  state  printing. 

1907. 


BENJAMIN  IDE  WHEELER.  Ph.D.,  LL.D.,  President  of  the   University. 


EXPERIMENT  STATION  STAFF. 

E.   J.   WICKSON,   M.A..    Director  and  Horticulturist. 

E.   W.   HILGARD.   Ph.D..  LL.D.,  Chemist. 

W.    A.    SETCHELL.    Ph.D.,    Botanist. 

ELWOOD  MEAD.  M.S.,  C.E.,  Irrigation  Engineer. 

C    W.   WOODWORTH,  M.S.,  Entomologist. 

R.     H.    LOUGHRIDGE,    Ph.D.,    Agricultural    Geologist    and    Soil    Physicist.       (Soils, 

Alkali.) 
M.  E.  JAFFA,  M.S.,  Nutrition  Expert,  in  charge  of  the  Poultry  Station. 
Gr.  W.   SHAW.  M.A.,  Ph.D.,  Agricultural  Technologist,  in  charge  of  Cereal  Stations. 
GEORGE  E.  COLBY,  M.S.,  Chemist.      (Fruits,  Waters,  Insecticides.) 
RALPH  E.  SMITH,  B.S.,  Plant  Pathologist  and  Superintendent  of  Southern  California 

Pathological   Laboratory  and  Experiment   Station. 
A.   R.   WARD,   B.S.A.,   D.V.M.,   Veterinarian  and  Bacteriologist. 

E.  W.  MAJOR,   B.Agr.,  Animal  Industry  and  Manager  of   University  Farm. 

F.  T.  BIOLETTI,   M.S.,   Viticulturist.      (Grapes,   Wine  and  Zymology.) 
H.   M.  HALL,  M.S.,  Assistant  Botanist. 

H.   J.   QUAYLE,  A.B.,   Assistant  Entomologist. 

W.    T.    CLARKE,    B.S.,    Assistant    Horticulturist    and    Superintendent    of    University 

Extension  in  Agriculture. 
JOHN   S.   BURD,  B.S.,   Chemist,  in  charge  of  Fertilizer  Control. 
C.  M.  HARING,  D.V.M.,  Assistant  Veterinarian  and  Bacteriologist. 

J.    W.    MILLS,    Assistant   Horticulturist,     \      CUrus  Experiment  station,  Riverside. 

T.   F.   HUNT,   B.S.,  "  ) 

E.   B.   BABCOCK,   B.S.,  Assistant  Plant  Pathologist. 

E.  H.  SMITH,  M.S.,  Assistant  Plant  Pathologist. 

H.  J.  RAMSEY  M.S.,  Assistant  Plant  Pathologist,  )     Southern  California  Pathologi- 

C.    O.    SMITH,    M.S.,  "  "  "  f         cal  Laboratory.     Whittier. 

R.   E.  MANSELL,  Assistant  in  Horticulture,  in  charge  of  Central  Station   Grounds. 

GEO.   W.    LYONS,   B.S.,   Assistant  in  Soil  Laboratory. 

RALPH  BENTON,   B.S.,   Assistant  in  Entomology. 

A.  J.   GAUMNITZ,  M.S.,  Assistant  in  Cereal  Investigations. 

HANS  C.   HOLM,  B.S.,  Assistant  in  Zymology. 

P.   L.   McCREARI,  B.S.,  Laboratory  Assistant  in  Fertilizer  Control. 

C.  WI^STERGAARD,    B.S.,  Assistant  in  Farm  Mechanics. 

M.  E.   STOVER,  B.S.,  Assistant  in  Agricultural  Chemical  Laboratory. 
RACHAEL  COR-R,  M.A.,  Assistant  in  Cereal  Laboratory. 

D.  R.  HOAGLAND,  A.B.,  Assistant  in  Agricultural  Chemical  Laboratory. 
D.   L.   BUNNELL,  Clerk  to  the  Director. 


JOHN  TUOHY,  Patron,  >_  Tulare  Substation,   Tulare. 

J.   T.   BEARSS,  Foreman,  ) 


J.   W.  ROPER,  Patron,  ) 

E    C    MILLER,   In  charge,        f 


University  Forestry  Station,  Chico. 
University  Forestry  Station,  Santa  Monica. 


ROY   JONES,   Patron,  I 

N.    D.    INGHAM,   Foreman,         f 
VINCENT     J.     HUNTLEY,     Foreman     of     California     Poultry     Experiment     Station, 

The  Station  publications  (Reports  and  Bulletins),  so  long  as  avail- 
able, will  be  sent  to  any  citizen  of  the  State  on  application. 


INSECTS  INJURIOUS  TO  THE  VINE  IN  CALIFORNIA. 

By  H.  J.  QUAYLE. 

California,  with  its  extensive  areas  of  vineyards  and  lack  of  extremes 
in  climate,  offers  suitable  conditions  for  the  development  of  a  con- 
siderable number  of  insect  pests  of  the  vine.  Here  also  the  large 
plantings  of  the  European,  or  vinifera,  vines  have  given  the  phylloxera 
an  opportunity  to  do  greater  damage  than  elsewhere  in  the  United 
States. 

Of  the  two  hundred  and  seventy-five  insects  we  have  recently  listed 
as  attacking  the  vine  throughout  the  world,  only  a  very  few  (a  dozen 
or  two)  are  really  of  any  economic  importance ;  all  the  others  being, 
generally,  but  casual  visitants.  Two  or  three  of  these  of  economic 
importance  attack  the  roots,  while  the  remainder  feed  upon  the  parts 
of  the  plant  above  ground. 

The  roots  are  sapped  of  their  juices,  rendered  knotty,  and  caused  to 
decay  by  the  phylloxera,  Strips  or  rings  of  the  bark  are  eaten  out  by 
the  root  worm,  and  the  fibrous  roots  are  devoured  by  wire  worms. 
The  juices  of  the  leaves  are  sucked  out  by  the  vine  hoppers,  irregular 
holes  eaten  away  by  flea  beetles  and  leaf  chafers,  or  chain-like  strips 
by  the  root  beetles;  the  edges  rolled  by  the  leaf-roller,  or  the  foliage 
devoured  completely  by  hawk  moth  larvae,  grasshoppers,  cut  worms  and 
army  worms.  The  young  buds  are  destroyed  by  the  flea  beetle  and  by 
cut  worms ;  and  the  shoots,  petioles,  pedicels,  and  berries  have  chain-like 
furrows  gouged  out  by  the  root  beetle. 

With  the  possible  exception  of  the  root  beetle,  all  the  insects  attacking 
the  vines  in  this  State  are  native  American  insects.  The  present 
bulletin  is  intended  to  give  simply  a  popular  account  of  the  more 
important  of  these.  More  or  less  extended  studies  have  been  carried  on 
during  the  past  year  on  the  vine  hopper  and  root  beetle,  and  these 
will  be  treated  of  in  separate  bulletins  and  only  summary  accounts 
given  here. 

PHYLLOXERA.* 

(Phylloxera  vastatrix  Planchon.) 

Historical — The  phylloxera  is  a  native  of  the  United  States  east  of 
the  Rocky  Mountains,  where  it  is  found  living  upon  the  wild  vines.  It 
is  a  minute  insect,  related  to  the  scale  insects  and  plant  lice. 

The  insect  was  probably  introduced  into  California  upon  vines,  cut- 
tings or  roots,  imported  from  France,  though  it  was  possibly  introduced 

*  Revised  from  Bulletin  No.  131,  by  F.  T.   Bioletti. 


100 


UNIVERSITY    OF   CALIFORNIA — EXPERIMENT   STATION. 


from  several  sources  and  at  several  points.  It  was  first  noticed  in  the 
southern  part  of  Sonoma  County,  in  the  valley  surrounding  the  old 
town  of  Sonoma,  about  1874.  By  1880  vines  killed  by  the  insect  had 
boon  found  in  Napa,  Solano,  and  Placer  counties,  and  hundreds  of 
acres  had  been  pulled  up  in  Sonoma  Valley.  Since  then  the  insect  has 
spread  to  all  the  important  grape-growing  regions  of  California  north 
of  Tehachapi*,  and  probably  not  less  than  fifty  thousand  acres  have 
been  destroyed. 


The  Insect. — The  phylloxera  occurs  normally  in  four  forms,  which 
have  been  called  by  Victor  Mayet: 

1.  The  gall  insect,  or  form  of  multiplication; 

2.  The  root  insect,  or  form  of  devastation; 

3.  The  winged  insect,  or  form  of  colonization ; 
•i.  The  sexual  insect,  or  form  of  regeneration. 

The  gall  insect  lives  upon  the  leaves,  and  is  the  commonest  form  on 
the  wild  vines  in  the  native  habitat  of  the  insect.     It  rarely  or  never 

occurs  in  California.  In  Europe 
it  is  found  often  upon  American 
and  rarely  upon  European  varie- 
ties. It  causes  little  swellings  or 
galls  upon  the  leaves  and 
younger  parts  of  the  vine,  which, 
though  sometimes  very  numer- 
ous, do  little  permanent  injury. 
I  The  chief  danger  from  the  gall 
form  is  that  it  multiplies  with 
astonishing  rapidity  and  mi- 
grates from  the  leaves  to  the  soil. 
Here  it  attacks  the  roots  and 
gives  rise  to  the  root  form,  which 
is  the  "form  of  devastation," 
the  one  which  finally  destroys 
all  the  vines  it  attacks  which  are 
■ -  non-resis1  ant. ' '  Every  insect  of  the  root  form  which  reaches  maturity 
Lays  about  twenty-five  or  thirty  eggs,  each  of  which  is  capable  of 
developing  into  a  new  egg-layer  needing  no  fertilization.  As  there  are 
from  five  to  seven  such  generations  during  the  year  the  increase  in 
numbers  is  extremely  rapid. 

Sometimes  during  the  summer,  usually  in  July  or  August,  some  of 
the  eggs  Laid  by  the  root  insects  may  develop  into  insects  of  slightly 
differenl    form,  called  nymphs.     They  are  somewhat  larger  than  the 

•The  phylloxera  is  said  to  have  been  found  once  in  Southern  California,  but  as 
uprooted  and  destroyed  the  insect  was  probably  extirpated. 


PIG.  1.     Under  side  of  grape  leaf  showing  galls 
caused    by    Phylloxera.    This   form   seldom,  if 
occurs  in  California. 


Bulletin  192. 


INSECTS    INJURIOUS    TO    THE    VINE. 


101 


normal  root  form  and  show  slight  protuberances  on  the  sides,  which 
finally  develop  into  wings.  These  are  the  winged  or  colonizing  insects, 
which  emerge  from  the  soil,  and,  though  possessing  very  weak  powers 
of  flight,  are  capable  of  sailing  a  short  distance,  and  if  a  wind  is 
blowing  may  be  taken  many  rods,  or  even  miles.  Those  which  reach 
a  vine  crawl  to  the  under  side  of  a  leaf  and  deposit  from  three  to  six 
eggs.  These  eggs  are  of  two  sizes,  the  smaller  of  which  produce  males 
and  the  larger  females.     The  females  arising  from  these  eggs,   after 

i 


fertilization,  migrate  to 
the  rough  bark  of  the 
two-year-old  wood,  where 
each  deposits  a  single 
egg,  called  the  winter 
egg,  which  remains  upon 
the  vine  until  the  fol- 
lowing spring.  The  in- 
sect which  hatches  from 
this  egg  in  the  spring 
goes  either  to  the  young 
leaves  and  becomes  a 
gall-maker,  or  descends 
to  the  roots  and  gives 
rise  to  a  new  generation 
of  egg-laying  root-feed- 
ers. 

The  normal  and  com- 
plete life  cycle  of  the 
phylloxera  appears  then 
to  be  as  follows :  Male 
and  female  insects  (one 
generation  in  autumn)  ; 
gall  insects  (one  to  five 
generations  while  the 
vines  are  in  leaf)  ;  root 
insects  (an  unknown  number  of  generations  throughout  the  year)  ; 
nymphs,  which  become  winged  insects  (one  generation  in  midsummer). 
The  gall  stage  may  be  omitted,  as  it  generally  is  in  California,  and  the 
insects  which  hatch  from  the  fertilized  eggs  laid  by  the  female  go 
directly  to  the  root  and  produce  offspring,  which  are  indistinguishable 
from  the  root  form  produced  in  the  normal  cycle.  For  how  many 
generations  the  root  form  can  exist  and  reproduce  without  invigoration 
supposed  to  come  from  the  production  of  the  sexual  form  is  not  known, 
but  certainly  for  four  years  and  probably  more.     The  gall  form  on 


/&^y 


FIG.  2  Root'Form  of  Phylloxera,  a,  healthy  root;  6,  root 
on  which  the  lice  are  working,  representing  the  knots  and 
swellings  caused  by  their  punctures;  c,  root  deserted  by 
lice  and  beginning  to  decay;  d,  d,  d,  show  how  the  lice 
appear  on  the  larger  roots ;  e,  the  nymph  ;  g,  winged  female. 
After  Riley. 


102  I'NlWKSirv    OV    CALIFORNIA EXPERIMENT   STATION. 

American  vines  may  probably  be  prevented  by  spraying  the  vines  in 
winter  to  kill  the  winter  eggs;  but  this  treatment  has  no  effect  on  the 
root  forms,  which  in  California  hibernate  abundantly  in  the  soil. 

All  forms  of  the  phylloxera  are  extremely  minute,  the  root  form 
being'  about  one  twenty-fifth  of  an  inch  long  when  it  reaches  the  adult 
__ -laying  stage,  and  little  more  than  half  this  length  when  young  and 
active.  It  is  just  large  enough  to  be  seen  by  the  unaided  eye  in  a 
good  light  when  its  presence  is  knowm,  and,  by  the  help  of  a  glass 
magnifying  five  diameters,  its  legs  and  antennae  are  plainly  visible. 
Its  color  is  light  greenish-yellow  in  summer,  and  somewhat  darker  in 
winter;  so  that  when  numerous  the  attacked  roots  appear  as  though 
dusted  in  spots  with  powdered  mustard  or  cinnamon.  The  newly 
hatched  insect  is  fairly  active,  and  at  first  moves  about  from  place 
to  place  on  the  roots,  but  finally,  when  it  reaches  the  egg-laying  stage, 
inserts  its  sucking-tube  into  the  root  and  remains  fixed. 

X at ure  of  Injury. — The  amount  of  nutriment  taken  from  the  vine 
by  such  minute  insects,  even  when  present  in  the  immense  numbers  in 
which  they  sometimes  occur,  is  not  sufficient  to  account  for  the  dis- 
astrous effect  upon  the  plant.  The  death  of  the  vine  is  due  to  the 
decay  which  sets  in  wherever  the  phylloxera  inserts  its  sucking-tube, 
for  a  swelling  is  produced,  composed  of  soft  tissue,  which  soon  decays. 
When  this  swelling  occurs  at  the  end  of  a  young  rootlet,  growth  in 
length  is  stopped;  when  it  occurs  on  larger  roots,  a  kind  of  "cancer" 
or  decay  spot  is  finally  formed,  which  soon  extends  around  the  root, 
and  all  belowT  the  point  of  attack  dies. 

During  the  first  year  or  two  after  a  vine  is  attacked  there  is  little 
apparent  damage.  In  fact,  the  effect  of  the  phylloxera  is  equivalent 
to  root  pruning,  and  in  some  cases  results  in  an  unusually  large  crop 
of  grapes.  The  year  after  this  crop,  however,  the  vine  having  endured 
the  double  strain  of  heavy  bearing  and  root  injury,  is  unable  to 
recuperate,  and  generally  dies.  In  rich  moist  soil  the  death  of  the 
vine  is  not  so  sudden,  and  two  or  even  more  crops  may  mature  after 
symptoms  of  the  disease  are  evident. 

Methods  of  Dispersal.  —  The  ways  in  which  new  vines  and  vineyards 

become  infested  may  be  classed  as  natural  and  artificial.     The  natural 

a  may  be  inferred  from  what  has  been  said  of  the  life  history  of 

the  insect.     From  a  vine  first  attacked  the  root  form  spreads  through 

the  soil  to  neighboring  vines  slowly,  but  continuously,  thus  forming 

the  so-called  "oil-spots."    A  typical  oil-spot  of  several  years'  standing 

/.ill  show  several  dead  vines  in  the  center,  then  a  ring  of  vines  with 

short  growth  and  no  grapes,  next  another  ring  where  the  growth 

A  <>\'  normal  vigor,  bul   where  the  crop  may  be  equal  to  or  larger 


Bulletin  192.  INSECTS  INJURIOUS  TO  THE  VINE.  103 

than  that  of  the  healthy  vines.  Such  a  spot  enlarges  its  area  year  after 
year  at  a  gradually  accelerating  rate  as  the  front  of  the  invading  army 
becomes  longer.  The  rate  of  advance  will  vary  with  the  soil  and  climate, 
but  will  probably  never  exceed  forty  or  fifty  feet  annually.  If  this 
were  its  only  method  of  spreading,  the  insect  could  be  controlled  or  even 
exterminated  with  comparative  ease.  Unfortunately,  it  is  able  to 
spread  much  more  rapidly  by  means  of  the  winged  form;  and  the 
rapidity  of  its  extension  over  the  south  of  France  was  due  principally 
to  this  agency.  In  California,  though  the  winged  form  has  been  found, 
it  seems  to  be  rare,  especially  in  the  central  valleys,  which  probably 
accounts  for  the  comparative  slowness  with  which  new  districts  have 
become  infested.  The  artificial  methods  of  dispersal  here  are  probably 
more  effectual  in  spreading  the  insect  than  the  natural.  The  insects 
are  taken  from  one  part  of  the  vineyard  to  another  on  pieces  of  the 
roots  of  infested  vines  adhering  to  the  plows  or  other  implements  used 
in  cultivation;  while  they  are  introduced  into  new  localities  on  rooted 
vines  or  cuttings  brought  from  infested  districts. 

METHODS    OP    COMBATING    THE    PHYLLOXERA. 

The  methods  to  be  used  in  resisting  this  foe  of  the  vineyardist  may 
be  divided  into  groups  corresponding  to  different  stages  of  infestation 
and  to  varying  local  conditions.  There  are  three  cases  to  be  distin- 
guished, viz :  1.  When  the  district  is  uninf ested ;  2.  "When  a  few  small 
infested  spots  are  known  in  the  district ;  3.  When  the  district  is  badly 
infested ;  i.  e.,  shows  many  and  widely  distributed  infested  spots,  even 
though  none  of  the  spots  are  large. 

1.  In  the  first  case,  all  efforts  should  be  directed  to  keeping  out  the 
pest,  and  the  only  effectual  means  is  a  rigidly  enforced  embargo  on  all 
material  capable  of  introducing  it.  Although  the  phylloxera,  so  far  as 
known,  feeds  on  nothing  but  the  vine,  there  is  always  danger  of  eggs 
or  insects  being  contained  in  the  earth  attached  to  any  kind  of  root. 
This  measure,  consistently  carried  out,  has  kept  the  province  of  Algiers 
free  from  infestation,  though  the  neighboring  province  of  Constantine 
has  been  a  prey  to  the  pest  for  many  years. 

2.  In  the  second  case,  where  the  insect  has  already  obtained  a  foot- 
hold, the  first  step  to  take  is  to  determine  as  nearly  as  possible  the 
exact  extent  of  the  infested  area.  If  it  is  found  to  be  confined  to  a 
small,  isolated  vineyard,  an  effort  should  be  made  to  completely  eradi- 
cate the  pest.  This  can  be  done  only  by  destroying  the  vineyard,  by 
subjecting  it  to  what  is  called  the  "death  treatment."  This  is  best 
done  (after  grubbing  up  the  vines  and  burning  them  on  the  ground) 
by  making  an  embankment  around  the  whole  vineyard  and  then 
running  water  on  to  it  until  it  is  converted  into  a  lake.     The  water 


104  UNIVERSITY   OF   CALIFORNIA — EXPERIMENT   STATION. 

should  be  kept  continuously  at  a  depth  of  at  least  six  inches  until  all 
the  insects  are  destroyed.  The  best  time  to  do  this  is  in  May  or  June, 
as  at  that  time  four  weeks  of  continuous  flooding  is  sufficient  to  kill 
both  insects  and  roots.  It  is  important  that  every  root  should  be  killed 
in  order  that,  if  any  insect  survives  the  flooding,  it  will  die  for  lack  of 
food.  Where  flooding  is  impracticable,  the  vines  should  be  grubbed 
out  and  burned  in  the  same  way,  and  the  ground  kept  clean  of  all 
growth  for  at  least  one  year.  This  is  in  order  that  any  suckers  which 
may  come  up  from  the  roots  may  be  destroyed  immediately.  If  crops, 
or  even  weeds,  are  allowed  to  grow,  some  of  these  suckers  may  escape 
observation  and  keep  the  insects  alive  to  spread  the  pest  the  next 
year.  If  the  affected  spot  is  not  too  large  it  is  well  to  disinfect  the  soil 
with  bisulfid  of  carbon.  This  is  applied  by  pouring  one  ounce  each 
into  holes  placed  two  feet  apart  all  over  the  land  to  be  treated.  These 
holes  should  be  about  one  foot  deep  and  can  be  made  with  a  small 
crowbar  or  dibble.  After  pouring  in  the  liquid,  the  hole  should  be 
closed  by  pressing  the  earth  into  it  with  the  foot. 

If.  however,  the  pest  has  obtained  a  foothold  in  several  vineyards  of 
the  district,  or  in  a  large  vineyard,  it  is  practically  hopeless  to  attempt 
to  eradicate  it.  In  this  case  all  we  can  reasonably  hope  to  do  is  to  delay 
the  spread  of  the  pest  as  much  as  possible,  and  in  the  meantime  to  place 
all  new  vineyards  on  a  permanently  phylloxera-resistant  basis.  Every 
infested  spot  in  the  district  should  be  diligently  sought  out  and  treated. 
The  treatment  consists  in  digging  up  and  burning  every  vine  in  each 
spot  which  shows  symptoms  of  attack,  together  with  at  least  three  rows 
of  apparently  healthy  vines  surrounding  them.  Disinfection  of  the 
soil  of  these  spots  by  flooding  or  with  bisulfid  of  carbon  is  then  advisable 
wherever  practicable,  but  in  any  case  these  spots  should  be  strictly 
isolated  in  all  farming  operations.  In  cultivating  the  healthy  parts 
of  the  vineyard,  to  pass  through  the  infested  spots  with  plows  or  hoes 
is  a  most  effective  method  of  accelerating  the  spread  of  the  insect. 

The  search  for  infested  spots  is  most  easily  and  thoroughly  done  in 
July,  or  August,  as  at  that  time  the  shortness  of  growth  in  the  " oil- 
spots"  is  most  readily  detected  and  the  insects  are  easily  found,  as  they 
are  in  large  numbers  on  the  surface  roots  and  generally  also  on  the 
trunk  of  the  vine  just  below  the  surface  of  the  soil.  The  search  for  and 
destruction  of  infested  spots  should  be  repeated  every  year:  and  if 
commenced  in  the  early  stages  of  infestation  and  prosecuted  with 
sufficient  thoroughness  in  every  vineyard  throughout  a  district,  will 
effectually  prolong  the  life  of  the  bulk  of  the  vines  for  many  years. 
As  soon  as  the  actual  presence  of  the  phylloxera  in  a  district  is  known 
and  all  hope  of  permanently  eradicating  it  is  abandoned,  the  embargo 
should    be   modified   to  the  extent  of  admitting  vine  cuttings.     These 


Bulletin  192.  INSECTS  INJURIOUS  TO  THE  VINE.  105 

should  be  introduced,  however,  under  strict  quarantine  regulations, 
including  disinfection  by  responsible  and  properly  instructed  persons. 
Rooted  vines,  or  cuttings  with  pieces  of  old  wood  attached,  should  still 
be  kept  out,  as  they  can  not  be  disinfected  with  any  certainty. 

3.  However  conscientiously  and  completely  these  measures  are  en- 
forced, a  time  will  arrive  sooner  or  later  when  the  cost  of  inspection  and 
eradication  will  be  greater  than  any  benefit  to  be  derived  from  them. 
We  are  then  face  to  face  with  the  third  set  of  conditions;  we  must 
accept  the  phylloxera  as  a  permanent  inhabitant  of  the  district,  and 
simply  consider  the  best  method  of  growing  our  vines  in  spite  of  its 
presence.  By  this  time  all  embargo  or  quarantine  regulations  are 
useless  and  should  be  repealed. 

Of  the  many  thousands  of  methods  proposed  and  tested  for  maintain- 
ing a  vineyard  in  spite  of  the  phylloxera,  but  very  few  have  been  of  the 
slightest  practical  value,  and  only  four  are  at  present  used  to  any 
important  extent.     These  methods  are: 

1.  Injection  of  carbon  bisulfid; 

2.  Flooding  or  submersion; 

3.  Planting  in  sand; 

4.  Planting  resistant  vines. 

The  first  two  methods  aim  at  destroying  the  insect;  the  last  two  at 
rendering  the  vines  immune  to  their  attack.  As  neither  of  the  insecti- 
cidal  methods  can  be  applied  with  sufficient  thoroughness  to  completely 
eradicate  the  pest  without  also  killing  the  vines,  the  treatments  have  to 
be  repeated  every  year  in  order  to  destroy  the  offspring  of  the  few 
insects,  which  escaped  the  treatment  of  the  previous  year.  For  this 
reason  these  methods  are  being  abandoned  everywhere,  especially  in  all 
new  plantings,  in  favor  of  the  others,  which  after  the  vineyard  is  prop- 
erly started,  involve  no  further  expense;  and  as  planting  in  sand  is  of 
very  limited  and  local  applicability,  it  may  be  said  that  at  present  the 
only  method  that  need  concern  grape-growers  in  California  very  seri- 
ously is  the  use  of  resistant  vines. 

Bisulfid  of  Carbon  Method. 

Bisulfid  of  carbon  is  a  liquid  which  volatilizes  very  rapidly  at  ordi- 
nary temperatures  and  gives  off  a  poisonous  and  highly  inflammable 
vapor.  This  vapor  is  heavier  than  air  and  therefore  gradually  replaces 
and  saturates  the  air  in  the  interstices  of  the  soil  when  the  liquid  is 
injected.  It  is  used  at  the  rate  of  from  one  hundred  and  twenty-five 
pounds  to  two  hundred  and  fifty  pounds  per  acre,  and  may  be  applied 
at  any  time  except  during  blossoming  and  ripening  of  the  fruit.  Two 
treatments,  one  directly  after  the  vintage  and  the  other  a  week  or  so 
before  blossoming,  give  the  best  results.  The  liquid  is  applied  by  pour- 
ing from  one-fourth  to  three-fourths  of  an  ounce  into  holes  made  from 


106  UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 

IS  to  '24  inches  apart  all  over  the  vineyard,  care  being  taken  not  to 
put  any  nearer  than  one  foot  from  a  vine.  The  holes  are  made  from 
12  to  15  inches  deep,  and  are  closed  immediately  after  pouring  in  the 
liquid  by  pressing  the  soil  with  the  foot.  The  holes  may  be  made  with 
an  iron  roil  or  dibble;  but,  where  the  method  is  employed  on  a  large 
s<  ale.  special  injectors  are  used,  which  much  facilitate  the  work.  Th<- 
injections  are  best  made  when  the  soil  is  fairly  firm,  and  when  it  is 
neither  very  wet  nor  very  dry.  This  method  succeeds  only  in  rich. 
deep,  loose  soils,  and  can  not  be  used  successfully  in  soil  containing 
much  clay,  or  on  dry,  rocky  hillsides  or  when  the  soil  is  saturated 
with  moisture.  It  is  most  effective  in  sandy  soils,  where  the  nature 
<>t  the  soil  is  itself  unfavorable  to  the  insect.  It  is  least  success- 
ful in  warmer  locations,  Avhere  the  insect  is  most  prolific  and  most 
harmful,  and  is  used  chiefly  in  the  cooler  locations  where  the 
phylloxera  does  least  damage.  Vines  which  are  much  weakened  by  the 
attacks  of  the  insects  can  not  be  successfully  treated,  and  all  treated 
vines  require  fertilization  and  most  thorough  cultivation.  The  annual 
cost  for  material  alone  would  be  from  $15  to  $25  per  acre,  at  the  present 
market  price  of  carbon  bisulfid. 

Submersion  Method. 

Submersion  is  a  cheaper  and  more  effective  method  of  controlling 
the  phylloxera,  but  is  necessarily  applicable  to  but  few  locations,  and 
even  where  most  successful  is  gradually  giving  way  to  the  more  satis- 
factory use  of  resistant  vines.  Its  chief  use  is  to  preserve  vineyards 
which  are  already  in  bearing,  and  it  may  be  of  use  temporarily  in  some 
locations  in  California.  In  submersion  the  vineyard  must  be  continu- 
ously covered  with  at  least  six  inches  of  water,  as  the  object  is  to  drown 
the  insects,  that  is,  to  kill  them  by  depriving  them  of  air.  If  the  sur- 
face becomes  exposed  even  for  a  brief  period,  air  will  be  absorbed  and 
the  insects  given  a  new  lease  of  life.  In  very  porous  soils  submersion 
is  impracticable  on  account  of  the  large  amount  of  water  required,  and 
ineffective  for  the  reason  that  the  rapid  passage  of  the  water  carries 
sufficient  air  into  the  soil  to  keep  the  insects  alive.  Submersion  is 
most  effective  in  destroying  the  insects  when  they  are  in  their  most 
active  condition,  that  is,  in  summer.  At  this  time,  unfortunately,  the 
vine  is  also  most  sensitive  to  injury.  The  most  favorable  time,  then. 
for  submersion  is  ae  soon  as  the  vines  have  ceased  active  growth  and 
before  the  phylloxera  have  entered  their  hibernating  or  dormant  con- 
dition. This  in  most  parts  of  California  will  be  some  time  in  Novem- 
ber. At  this  period  the  flooding  need  last  but  a  week  or  ten  days;  a 
month  Later,  two  or  three  weeks:  while  during  the  remainder  of  the 
vinter  little  good  results  unless  the  submersion  is  prolonged  for  thirty- 


Bulletin  192.  INSECTS  INJURIOUS  TO  THE  VINE.  107 

five  or  forty  days,  and  indeed  in  some  soils  of  the  extreme  south  of 
France  two  months  has  been  found  necessary.  As  the  insect  is  most 
susceptible  in  midsummer,  it  was  at  one  time  thought  that  a  copious 
irrigation  at  that  time  sufficient  to  destroy  most  of  the  insects  without 
injuring  the  vines  could  be  effected.  At  present  a  flooding  in  July  for 
not  exceeding  forty-eight  hours  is  practiced  in  a  few  places,  but  only  to 
supplement  winter  flooding,  or  the  injection  of  bisulfid.  The  insecti- 
cidal  value  of  the  short  submersion  which  the  vines  will  withstand  at 
this  time  seems  to  be  very  slight.  Its  main  value  seems  to  be  in 
prompting  a  vigorous  growth  of  new  rootlets  to  replace  those  that  have 
been  injured. 

Planting  in  Sand  Method. 

Though  no  thoroughly  satisfactory  explanation  has  been  given,  the  fact 
is  established  that  in  certain  very  sandy  soils  vines  are  uninjured  by 
phylloxera.  All  sandy  soils  are  unfavorable  to  the  increase  of  the 
insect,  and  vines  planted  in  them  die  more  slowly  than  in  others;  but 
for  complete  immunity  the  soil  must  contain  at  least  sixty  per  cent  of 
siliceous  sand.  The  looser  and  more  fine-grained  the  sand,  the  more 
resistance  it  offers  to  the  insect.  Sands  containing  notable  quantities 
of  clay,  all  those  in  fact  which  have  a  tendency  to  form  lumps  or 
"  cake,"  offer  less  resistance. 

Resistant    Vines. 

The  most  satisfactory  method  of  combating  phylloxera  is  the  use  of 
resistant  vines,  because  it  is  applicable  to  all  conditions  and  is  the  most 
economical  in  the  end.  A  resistant  vine  is  one  which  is  capable  of 
keeping  alive  and  growing  even  when  phylloxera  are  living  upon  its 
roots.  Its  resistance  depends  on  two  facts:  1st,  that  the  insects  do  not 
increase  so  rapidly  on  its  roots;  and,  2d,  that  the  swellings  of  diseased 
tissue  caused  by  the  punctures  of  the  insects  do  not  extend  deeper  than 
the  bark  of  the  rootlets  and  are  sloughed  off  every  year,  leaving  the 
roots  as  healthy  as  before.  The  wild  vines  of  the  Mississippi  valley 
states  have  evolved  in  company  with  the  phylloxera,  and  it  is  naturally 
among  these  that  we  find  the  most  resistant  forms.  No  vine  is  per- 
fectly immune  in  the  sense  that  phylloxera  will  not  attack  it  at  all; 
but  on  the  most  resistant  the  damage  is  so  slight  as  to  be  impercep- 
tible. The  European  vine  ( Vitis  vinifera  L.)  is  the  most  susceptible  of 
all,  and  all  the  grapes  cultivated  in  California,  with  a  few  unimportant 
exceptions,  belong  to  this  species.  Between  these  two  extremes  we  find 
all  degrees  of  resistance,  which  is  expressed  by  a  series  of  numbers 
ranging  from  20,  indicating  the  highest  possible  resistance,  to  0,  indi- 
cating the  utmost  susceptibility.     The  following  table  shows  the  resist- 


108 


UNIVERSITY    OF    CALIFORNIA FXPFRl.MENT    STATION. 


ance  (according  to  Viala  and  Ravaz  and  other  authorities)  of  some  of 
the  best  known  species  and  varieties: 

Comparative  Resistance  to  Phylloxera. 


Species — Wild  Vines. 


Cultivated     Varieties     and     Hybrids. 


Viris  rotundifolia   19 

Viris  vulpina    (Riparia ) 18 

Viris  rupestris    18 

Vitis  Beriandieri   17 

Viris  aestivalis   16 

Viris  labrusca    5 

Viris  californica    4 

Viris  vinifera    0 


Gloire  de  Montpellier  (Riparia)  ....  18 

Riparia   X   Rupestris  3309 IS 

Rupestris    Martin 18 

Rupestris  St.   George 16 

Riparia   X    Solonis   1616 16 

Solonis     14 

Lenoir    : 12 

Isabella    5 


The  degree  of  resistance  necessary  for  the  production  of  good  crops 
varies  with  the  character  of  the  soil.  The  resistance  expressed  by  the 
numbers  16  to  20  is  sufficient  for  all  soils.  A  resistance  of  14  or  15  is 
sufficient  in  sandy  and  moist,  rich  soils,  where  the  vine  can  readily 
replace  the  rootlets  as  fast  as  they  are  destroyed.  Fairly  successful 
vineyards  have  been  established  with  vines  having  a  resistance  of 
less  than  14,  but  as  the  vines  become  old  the  lack  of  resistance  is 
generally  shown  by  a  weakening  of  the  vine  and  a  falling  off  of  the 
crop.  Many  vineyards  in  the  south  of  France  grafted  on  Lenoir  wThich 
formerly  bore  well,  have  now  to  be  treated  with  injections  of  bisulfid  of 
carbon.  For  the  above  reason  it  is  advisable  to  reject  all  vines  with  a 
resistance  of  13  or  under,  especially  as  vines  with  greater  resistance 
can  nowT  be  obtained  for  practically  all  conditions. 

Resistant  vines  are  of  two  kinds:  (a)  Those  which  are  grown  for  the 
grapes  they  produce,  and  (b)  Those  which  are  useful  only  as  stocks  on 
which  to  graft  the  non-resistant  varieties.  The  former  are  called 
"Direct  producers"  and  the  latter  "Resistant  stocks." 

(a)  Direct  Producers. — When  the  phylloxera  commenced  to  destroy 
the  vineyards  of  Europe,  the  natural  attempt  was  made  to  replace  them 
with  the  varieties  of  vines  which  had  proved  successful  in  the  United 
States,  where  the  insect  was  endemic.  These  varieties,  however,  all 
proved  unsatisfactory.  Some,  like  the  Concord  and  Catawba,  were 
insufficiently  resistant,  and  although  they  could  be  grown  where  the 
ere  cold  of  winter  impeded  the  prolificness  of  the  phylloxera,  they 
quickly  succumbed  in  the  milder  grape-growing  sections  of  Europe.* 
Most  of  them  were  poor  bearers  compared  with  the  prolific  European 
vines,  are!  finally  the  character  of  their  fruit  differed  so  widely  from 

*  In  California  these  and  other  Labrusca  varieties  and  hybrids  resist  very  little 
\<,x\-^-v  th:irj   Vinifera  vines. 


Bulletin  192.  INSECTS  INJURIOUS  TO  THE  VINE.  109 

what  Europeans  were  accustomed  to,  that  there  was  little  sale  for  the 
fruit,  and  the  wine  could  compete  with  only  the  very  poorest  quality  of 
Vinifera  wines,  and  brought  a  very  inferior  price.  A  few  of  the  varieties 
introduced  during  that  first  period  are  still  grown  to  a  limited  extent  in 
France,  chiefly  the  Othello  and  the  Lenoir.  They  are  being  gradually 
abandoned,  however,  as  their  crops  are  unsatisfactory,  and  in  many 
localities  can  be  maintained  only  by  the  aid  of  injections  of  bisulfid. 
For  some  years  the  search  for  a  suitable  producer  was  almost  abandoned 
by  practical  men,  the  use  of  resistant  stocks  having  been  so  fully 
successful.  Lately,  however,  renewed  efforts  have  been  made  and 
several  new  direct  producers  are  being  advocated  and  planted  to  some 
extent.  The  merit  of  these  new  varieties,  however,  is  chiefly  their 
resistance  to  Peronospora  and  black  rot.  Phylloxera  resistance  is  con- 
sidered of  much  less  importance  by  their  most  ardent  advocates,  and 
indeed  the  advice  is  generally  given  to  graft  some  of  the  best  of  these 
direct  producers  upon  phylloxera-resistant  stock. 

(b)  Resistant  Stocks. — Though  high  resistance  to  phylloxera  is  essen- 
tial in  a  grafting  stock,  there  are  other  characteristics  equally  necessary. 
The  Rotundifolia  (Scuppernong),  which  has  the  highest  resistance  of 
any  vine,  is  useless  as  a  stock  on  account  of  the  impossibility  of  grafting 
it  with  any  Vinifera  variety.  This  is  due  to  a  lack  of  affinity,  which 
means  a  lack  of  similarity  in  structure  and  composition  between  the 
tissues  of  the  stock  and  those  of  the  scion.  This  lack,  in  extreme  cases, 
results  in  an  imperfect  and  temporary  union,  but  when  not  excessive, 
only  in  a  slight  decrease  of  vigor.  The  affinity  is  not  perfect  between 
Vinifera  varieties  and  any  resistant  stock,  but  in  the  case  of  Riparia 
and  Rupestris  is  generally  sufficient  to  insure  permanence  to  the  union, 
and  the  slight  decrease  of  vigor  consequent  often  results  in  an  increase 
of  fruitfulness.  It  is  for  this  reason  that  certain  varieties  when  grafted 
on  resistant  stocks,  especially  on  Riparia,  often  bear  larger  crops  than 
when  grown  on  their  own  roots.  Not  all  varieties  of  Vinifera  have  the 
same  affinity  for  the  same  stock.  For  this  reason  it  is  desirable  to  be 
cautious  about  making  new  or  untried  grafting  combinations  on  a  large 
scale.  Some  varieties,  such  as  Carignan,  Petite  Sirah,  Clairette,  and 
Cabernet  Sauvignon,  do  excellently  on  all  stocks;  while  others,  such  as 
Mondeuse  and  Gamay,  do  not  make  a  very  good  union  with  any  of  the 
thoroughly  resistant  stocks.  The  Petit  Bouschet  and  Cinsaut  make 
very  poor  unions  with  any  variety  of  Riparia,  but  do  fairly  well  on 
Rupestris  St.  George.  The  Pinot  Noir  makes  a  vigorous  growth  upon 
Rupestris  St.  George,  but  bears  much  more  prolifically  upon  Riparia 
Gloire;  while  the  Mataro  does  not  bear  on  Rupestris  St.  George  and 
makes  poor  unions  with  Riparia  Gloire.* 

*  Reconstitution  du  Vignoble,  par.  P.  Gervais.     1900. 


110  UNIVERSITY   OF   CALIFORNIA — EXPERIMENT   STATION. 

>  lection.  A  very  serious  defect  of  many  resistant  stocks  is  a  slender 
habit  of  growth.  This  is  true  of  most  of  the  vines  found  growing  wrild, 
and  cuttings  from  such  vines  make  poor  grafting  stock  for  the  stout 
Vinifera  varieties,  which  will  produce  a  trunk  four  inches  in  diameter 
while  the  stock  is  growing  only  two  inches.  This  is  particularly  true 
of  the  wild  Riparias.  For  this  reason  great  care  has  been  exercised  in 
selecting  the  stronger-growing  vines,  and  at  present  we  have  selected 
Riparia  varieties  which  almost  equal  Vinifera  in  the  stoutness  of  their 
trunks.  The  best  of  these  are  the  Riparia  Gloire  de  Montpellier  and 
Riparia  Grande  Glabre — the  first  of  which  has  given  the  best  result-  in 
California. 

Adaptation. — The  European  vine  is  remarkable  among  cultivated 
plants  for  the  wide  range  of  soils  in  which  it  will  succeed.  We  find 
vineyards  producing  satisfactory  crops  on  the  lightest  sands  and  on  the 
heaviest  clays,  on  the  dry  hilltops  and  in  the  low,  moist  plains.  This 
is  not  the  case  wTith  resistant  stocks.  Some,  such  as  the  Rupestris  vari- 
eties, are  suited  to  the  driest  soils;  others,  like  the  Riparia  varieties, 
grow  well  only  in  rich,  moist  soils.  The  question  of  adaptation,  then, 
of  resistant  stocks  to  various  soils  is  of  the  greatest  importance  if  we 
are  to  obtain  the  best  results. 

After  rejecting  all  unselected  and  unnamed  varieties,  such  as  tin- 
ordinary  Rupestris  and  Riparia,  which  have  caused  so  much  disap- 
pointment and  loss  on  account  of  their  poor  growth,  and  all  insuffi- 
ciently resistant  varieties,  such  as  Lenoir,  which  have  succeeded  only 
in  the  richest  soils,  our  choice  of  a  resistant  for  a  particular  soil,  climate, 
and  scion  must  depend  on  its  qualifications  as  regards  affinity  and 
1 1  Captation. 

After  testing  thousands  of  varieties  and  hybrids  originated  in  Europe 
and  America,  a  few  have  been  selected  as  the  best  for  practical  pur- 
poses. In  France  a  fairly  good  resistant  stock  has  been  found  for 
nearly  every  soil.  In  California  little  systematic  work  has  been  done 
in  this  respect,  and  we  still  have  the  intricate  problems  of  adaptation 
to  solve  for  most  localities.  We  can,  however,  profit  to  some  extent  by 
the  experience  of  Europe,  and  some  of  the  best  varieties  have  been 
partially  tested  here  and  give  great  promise. 

Disinfection  of  Cuttings. 

The  most  effective  method  of  treating  cuttings  suspected  of  being 
infested  with  phylloxera  is  to  expose  them  to  the  fumes  of  bisulfid  of 
carbon.  The  treatment  with  liquid  insecticides  is  not  nearly  so  reliable. 
ag  Professor  Hilgard  pointed  out  many  years  ago,  on  account  of  the 
difficulty  of  wetting  the  buds  of  many  varieties,  owing  to  their  protect- 
ive covering  of  woolly  hairs. 


Bulletin  192.  INSECTS  INJURIOUS  TO  THE  VINE.  Ill 

The  method  of  using  the  bisulfid  is  as  follows:  Place  the  cuttings  in  a 
barrel,  vat,  or  box  made  tight  by  means  of  a  thick  coat  of  paint,  or  of 
paper  pasted  on  the  inside.  On  top  of  the  cuttings  place  a  saucer  or 
other  shallow  dish,  and  into  this  pour  the  bisulfid  of  carbon.  An  ordi- 
nary saucer  will  hold  enough  for  a  box  three  feet  cube  or  a  two-hun- 
dred-gallon vat.  For  larger  receptacles  it  is  better  to  use  two  or  more 
saucers.  Deeper  vessels  will  not  do,  as  the  saturation  is  not  sufficiently 
rapid.  After  pouring  the  bisulfid  into  the  saucer,  cover  the  box  with 
an  oiled  canvas  sheet  or  other  tight-fitting  cover,  and  allow  to  stand 
for  from  forty-five  to  ninety  minutes.  At  the  end  of  this  time  there 
should  be  a  little  of  the  bisulfid  left.  If  it  has  all  evaporated  this  is 
proof  that  insufficient  was  used.  No  flame  lights  should  be  used,  as 
the  liquid  burns  easily  and  the  fumes  form  an  explosive  mixture  with 
the  air.  Care  should  be  taken  not  to  spill  any  of  the  liquid  on  the  cut- 
tings, as  it  may  kill  them.  It  is  advisable  to  cut  off  about  half  an  inch 
of  the  lower  end  of  the  treated  cuttings  before  planting,  as  the  vapor 
injures  the  open  pith.  Besides  disinfecting  the  cuttings  in  this  way,  all 
the  packing  material  in  which  they  come  should  be  burned  or,  if  valu- 
able, dipped  in  boiling  water.  Practically,  it  is  impossible  to  disinfect 
rooted  cuttings  satisfactorily  on  account  of  the  difficulty  of  killing  all 
the  phylloxera  without  seriously  injuring  the  vine  roots. 


THE  VINE  HOPPER. 

(TypJdocyba  comes  Say.) 

The  vine  hopper  (often  called  incorrectly  the  vine  thrips)  is  the  most 
widely  distributed  and  most  uniformly  present  of  all  the  grape  insects 
occurring  in  the  State.  It  occurs  in  injurious  numbers,  however,  chiefly 
in  the  Sacramento  and  San  Joaquin  valleys.  It  is  also  present  in  the 
coast  counties,  but  rarely  in  sufficient  numbers  to  do  much  injury. 
Another  larger  species  (Tettigonia:  atropunctata)  occurs  in  these  local- 
ities and  sometimes  does  considerable  injury  in  the  early  part  of  the 
season. 

The  principal  injury  occasioned  by  this  insect  is  due  to  the  extraction 
of  the  plant  juices.  These  are  sucked  out  by  means  of  a  sharp  beak  or 
proboscis,  which  is  inserted  into  the  plant  tissues.  The  first  evidence 
of  injury  is  a  pale  spot  around  the  point  of  puncture.  As  these  spots 
become  more  numerous  the  leaf  assumes  a  variegated  appearance,  due 
to  these  pale  spots,  which  indicates  a  lack  of  chlorophyll  or  green  mat- 
ter. As  the  injury  increases  the  leaf  becomes  pale  yellow  in  color,  and 
later  dries  up  and  falls  to  the  ground.  The  leaves  first  attacked,  and 
those  which  suffer  most  throughout  the  season,  are  about  the  crown  of 


112  UNIVERSITY   OF   CALIFORNIA EXPERIMENT   STATION. 

the  vino.  In  the  vines  thus  infested,  all  the  leaves  within  a  radius  of 
a  foot  or  two  from  the  center  of  the  vine  have  dried  up  and  many  have 
fallen  off  by  the  end  of  June  or  July,  thus  exposing  the  fruit.  This 
early  loss  of  foliage  prevents  the  berries  from  maturing  properly.  The 
sugar  content  of  the  grape  is  much  reduced,  and  in  table  varieties  the 
characteristic  coloring,  which  is  important,  is  not  attained.  In  addition, 
the  fruit  is  badly  soiled  by  the  excrement  of  the  hoppers — which  serves 
to  hold  dust  and  dirt  or  offers  suitable  conditions  for  the  growth  of 
fungi — and  often  this  covers  the  leaves  so  thoroughly  as  to  interfere 
with  respiration.  The  loss  of  leaves,  or  any  interference  with  their 
normal  functions,  also  prevents  the  proper  ripening  of  the  canes  for  the 
next  year's  wood,  and  thus  the  vine  may  require  a  year  or  more  to 
recover  from  severe  cases  of  hopper  injury. 

This  insect  is  not  more  than  a  tenth  of  an  inch  long  and  of  a  pale 
yellow  color,  prettily  marked  with  irregular  red  markings. 
They  are  usually  found  on  the  under  side  of  the  leaves, 
and  if  these  are  turned  over  carefully  the  insects  may  be 
seen.  They  are  very  readily  disturbed,  and  often  emerge 
from  a  vine  in  swarms,  so  that  they  are  not  likely  to  be 
mistaken  for  any  other  insect  pest  of  the  vineyard. 

Life  History. — The  life  history  of  this  insect  as  it  has 
fig.  3.  The      been  worked  out  in  this  State  during  the  past  year  is, 

grape  leaf-  °  r  J 

hopper.  briefly,  as  follows: 

Hoppers  which  have  reached  full  growth  on  the  vine  during 
the  fall  or  late  summer  remain  in  the  vineyard  or  vicinity  during 
the  winter  season.  During  the  colder  days  they  are  more  or 
less  dormant  and  will  be  found  hiding  under  the  leaves,  or  other 
rubbish  in  the  vineyard,  or  sheltered  in  the  vegetation  along  the 
bordering  fences  or  roadsides. 

During  the  warmer  days  of  winter  they  become  fairly  active  and  will 
be  found  feeding  on  whatever  vegetation  happens  to  be  growing  among 
the  vines  or  in  the  vicinity. 

As  soon  as  the  vines  come  into  leaf  in  the  spring,  they  leave  their 
more  varied  food-plants  of  winter  and  attack  the  vine  exclusively. 
After  feeding  upon  the  grape  foliage  for  about  a  month,  egg-laying 
begins.  This  in  the  Lodi  section  during  the  past  season  was  about  May 
first.  The  eggs  are  laid  just  beneath  the  epidermis,  on  the  lower  side 
of  the  leaf,  rarely  on  the  upper  surface.  They  may  be  distributed  any- 
where over  the  surface  and  are  most  difficult  to  see  unless  one  is  famil- 
iar with  their  appearance.  We  have  counted  more  than  seven  hundred 
of  these  egge  in  a  single  leaf.  One  hopper  will  lay,  on  an  average, 
nty-five  to  one  hundred  eggs,  during  a  period  of  from  one  to  two 
months.     The   eggs  from   these  over-wintering    hoppers  require  about 


Bulletin  192.  INSECTS  INJURIOUS  TO  THE  VINE.  113 

twenty  days  to  hatch.  Then  the  young  or  nymph  appears  and  begins 
at  once  to  feed  upon  the  leaves.  It  is  a  very  small  creature,  white  in 
color,  with  conspicuous  red  eyes.  After  feeding  for  a  few  days  it 
molts  or  sheds  its  skin.  Altogether  it  molts  five  times,  requiring  a 
period  of  from  seventeen  to  twenty  days  before  the  last  molt,  when  the 
full-fledged  winged  hopper  is  produced. 

After  feeding  for  a  couple  of  weeks  as  an  adult  hopper,  pairing  begins 
and  a  week  later  another  set  of  eggs  is  deposited.  These  require  but 
from  eight  to  twelve  days  to  hatch,  a  shorter  period  than  the  first  lot 
required,  probably  on  account  of  the  higher  temperature  later  in  the 
summer.  Thus  the  life  cycles  are  repeated.  Nymphs  arising  from  the 
eggs  laid  by  the  over-wintering  hoppers  began  appearing  about  the 
middle  of  May,  and  those  from  the  following  brood  about  the  middle 
of  July,  making  two  broods  during  the  season. 

CONTROL    MEASURES. 

Farm  Practices. — Since  the  over-wintering  hoppers  are  sheltered 
in  large  numbers  by  the  leaves  which  are  blown  together  in  bunches 
in  the  vineyard,  and  other  rubbish  along  the  borders,  clean  culti- 
vation will  help  to  reduce  their  numbers.  The  hoppers  depend 
for  food  upon  what  they  can  obtain  in  the  vineyard  or  vicinity,  and  if 
the  weeds  and  other  vegetation  are  kept  down  many  will  starve  or  be 
obliged  to  go  elsewhere  for  food.  When  the  vineyard  is  plowed  in  early 
spring  before  the  vines  come  into  foliage,  the  hoppers  will  all  leave  the 
vineyard  and  feed  upon  the  nearest  available  vegetation,  which  is 
usually  about  the  borders.  If  these  borders  and  roadsides  could  be 
kept  free  and  a  general  movement  for  clean  culture  inaugurated  in  a 
neighborhood,  it  might  do  much  to  prevent  the  hoppers  from  becoming 
excessive,  but  because  of  the  possibility, of  extensive  migrations  in  the 
spring  the  work  of  any  individual  grower  might  be  of  little  avail, 
though  such  migrations  did  not  occur  at  Lodi  the  present  season  and 
individual  work  would  undoubtedly  have  been  useful. 

The  Hopper  Cage. — So  far  as  the  work  has  progressed  this  year  the 
most  satisfactory  method  of  control  is  in  the  use  of  a  hopper  cage  to  be 
used  in  the  early  spring  when  the  young  shoots  of  the  vine  are  about 
four  or  five  inches  long.  This  is  to  be  supplemented,  if  necessary,  by 
spraying  for  the  first  brood  of  nymphs  early  in  June. 

The  hopper  cage  (Fig.  4)  consists  of  a  frame  work  of  laths  over  which 
is  tacked  a  double  layer  of  mosquito  wire  netting  or  a  single  20-mesh 
wire  screen.  The  bottom  consists  of  a  shallow  pan  or  tray  made  by 
turning  up  about  an  inch  of  the  edges  of  a  sheet  of  light  galvanized  iron. 
One  entire  side  of  the  cage  is  left  open,  and  there  is  a  V-shaped  opening 
in  the  tray  at  the  bottom  which  allows  the  cage  to  be  pushed  over  the 
2— Bul.  192 


114 


UNIVERSITY  QF   CALIFORNIA — EXPERIMENT   STATION. 


vine.  The  base  of  the  V-shaped  opening  in  the  bottom  is  padded  with 
leather  and  the  vine  is  bumped  and  the  hoppers  jarred  off,  at  the  same 
time  that  the  cage  is  being  swung  into  position.  The  sides  of  the  cage 
and  the  tray  at  the  bottom  are  smeared  with  crude  oil,  and  the  hoppers 
as  they  are  jarred  off  are  caught  in  the  oil. 

If  there  is  a  breeze  blowing  the  cage  can  be  operated  with  the  open 
side  facing  the  wind  and  practically  no  hoppers  will  escape.  If,  how- 
ever, the  day  is  calm  and  warm  and  the  hoppers  are  particularly  active 


FIG.  4.    The  hopper  cage. 


a  curtain  can  readily  be  dropped  over  the  open  side  as  the  cage  is  pushed 
onto  the  vine,  and  it  will  prevent  any  from  escaping. 

The  V-shaped  opening  which  might  allow  hoppers  to  drop  to  the 
ground  in  front  of  the  vine  can  be  covered  with  canvas,  as  follows: 
Take  two  pieces  of  canvas  about  the  shape  of  the  opening  and  a  little 
wider.  Double  this  once  on  itself  and  between  the  two  layers  sew  in 
pieces  of  three-fourths  inch  rubber  tubing  transversely.  These  are  then 
firmly  tacked  on  the  sides  of  the  opening  as  shown  in  the  figure.  This 
will  allow  the  cage  to  be  pushed  in  on  the  vine  and  the  flexibility  of 
the  tubing  will  bring  the  canvas  immediately  into  position  again. 
This,  with  the  curtain  in  front,  shuts  off  all  possibility  of  escape. 

This  device-  can  be  used  to  advantage  only  when  the  vines  are  headed 


Bulletin  192.  INSECTS  INJURIOUS  TO  THE  VINE.  115 

some  little  distance  from  the  ground  so  that  the  bottom  of  the  cage  can 
be  pushed  under  them.  While  it  is  generally  conceded  that  this  is  the 
proper  way  to  prune  most  vines,  there  are  still  some  vineyards  in  the 
State  where  the  vines  have  been  headed  immediately  at  the  ground,  and 
some  others  have  been  given  this  form  by  frost.  For  such  vines,  if  the 
cage  is  to  be  used  at  all,  it  must  be  used  with  no  bottom,  or,  at  least,  a 
less  complete  one  than  the  cage  described. 

This  cage  should  be  used  in  the  early  spring  when  the  shoots  are  not 
more  than  four  or  five  inches  long.  At  this  time  all  the  hoppers  will 
be  found  on  the  vines  and  they  have  not  yet  laid  any  eggs.  The  cage 
need  not  be  much  larger  than  the  diameter  of  the  vines  after  pruning. 
The  size  of  the  cage  and  the  opening  at  the  bottom  should  be  made 
according  to  the  size  of  the  vines  to  be  treated. 

This  cage  can  be  used  at  comparatively  little  expense — there  being 
practically  no  cost  for  materials — as  the  chief  outlay  is  the  time  of  the 
men  employed  in  handling  it.  Such  a  cage  can  be  manipulated  by  a 
couple  of  men,  and  for  small  vines,  four  or  five  years  old  or  under,  it 
may  be  handled  by  only  one.  Four  or  five  acres  can  be  covered  in  a 
day  and  the  oil  used  can  be  bought  for  a  trifle. 

If  this  cage  is  conscientiously  used  it  will  catch  from  85  to  95  per 
cent  of  the  hoppers,  and  this,  at  a  time  before  any  eggs  have  been  laid, 
ought  to  control  the  situation  for  the  season.  No  migrations  were 
observed  during  the  past  season  until  about  the  middle  of  July,  and  if 
the  vines  have  not  already  been  injured,  they  will  not  suffer  much  loss 
from  an  attack  at  this  time  or  later. 

Spraying. — If  for  any  reason  the  above  method  has  not  been  used,  or 
satisfactorily  done,  the  next  most  successful  method  is  to  spray  for  the 
first  brood  of  nymphs  or  young.  The  time  for  doing  this  during  the 
past  season  at  Lodi  was  about  the  first  of  June,  but  the  date  will  vary 
with  the  season  and  location.  The  sprays  which  were  found  to  be 
satisfactory  were  the  whale-oil  soap  solution  and  the  resin  spray.  The 
materials  used  in  these  sprays  were  one  pound  of  soap  or  resin  to  fifteen 
gallons  of  water.  About  one- fourth  of  a  pound  of  ordinary  lye  should 
be  used  to  each  pound  of  resin  to  make  it  dissolve  thoroughly. 

An  "upper  shot"  spray  should  be  used,  and  the  best  type  of  nozzle 
for  this  is  an  eddy  chamber  Vermorel,  where  the  liquid  is  turned  at 
right  angles  in  the  chamber.  This  style  does  away  with  anything  to 
catch  among  the  canes,  and  such  a  nozzle  may  be  poked  anywhere 
through  the  vine  without  being  caught. 

Thoroughness  is  most  important  here,  since  the  spray  will  kill  no 
more  than  it  hits.  The  under  side  of  every  leaf  must  be  wet  with  the 
solution.  If  this  is  done  by  the  first  of  June  when  the  growth  is  small, 
it  is  not  an  exceedingly  difficult  task.     This  spraying  is  expected  to  kill 


116  UNIVERSITY    OF   CALIFORNIA — EXPERIMENT   STATION. 

the  nymphs  only.  It  will,  of  course,  kill  a  few  adults,  but  the  number 
of  these  will  be  very  small.  In  addition  to  the  adults  which  escape, 
there  are  eggs  at  this  time  which  the  spray  will  not  prevent  from 
hatching.  While  this  means  of  control  will  kill  a  very  satisfactory 
percentage  of  the  nymphs,  many  adults  will  escape,  and  the  eggs  will 
he  left  to  hatch  later. 

The  advantage  of  the  cage  method  is  that  it  is  more  thorough  and 
effective.     The  hoppers  are  attacked  at  a  critical  time;  i.  p..  when  all 
adults  are  in  the  vineyard;   and  as  they  have  not  commenced  to  breed 
or  to  lay  eggs  the  work  is  effective  in  greatly  diminishing  the  nun; 
of  succeeding  generations. 


THE  IMPORTED  GRAPE-ROOT  WORM. 

(Adoxus  vitis  Fourcroy.) 

This  pest  of  the  vine  has   been  reported  from  different  parts  of  the 
State  for  a  number  of  years,  but  until  a  year  or  two  ago  it  was  unknown 

as  a  root  feeder.     In 

our  literature    it  has 

commonly  gone  by  the 

name   of   flea    beetle, 

I  \  and     probably    most 

J  \         growers    know    it    1  >y 

/    ^  \       that  name.     It  is  not. 

however,  a  flea  beetle 

J?Mf  m  *^  at  aU>  since  it  neither 

|   jumps  as  indicated  by 
I    the  name,  nor  is    its 
life  history  similar  to 
that  of  a  flea  beetle. 
It    was    called    by 
i  Matthew  Cooke,  in  his 

book  entitled  "  Inju- 
rious Insects  of  the 
Orchard  and  Vine- 
yard," the  "  Imported 

Grape    Flea    Beetle." 
FIG.  5.    Adult  of  the  grape-root  worm. 

Since,   however,   it   is 

>ot    beetle   rather  than  a  flea  beetle  and  is  probably  an  imported 

,nr|    in    its   life   history  is  almost  identical  with  the   grape-root 

worm  of  the  Eastern  States,  we  propose  giving  it  the  common  name  of 

[mported  Grape-Root  Worm. 


■ 


(•) 


Bulletin  192. 


INSECTS    INJURIOUS    TO    THE    VINE. 


117 


This  insect  has  done  considerable  damage  in  this  State  within  the 
past  two  or  three  years,  and  promises  to  be  a  serious  enemy  of  the  vine- 
yardists  unless  held  in  check.  The  grape-root  worm  of  the  Eastern 
States,  identical  in  all  important  respects  with  this  one,  is  one  of  the 
most  serious  pests  the  grape-grower  in  that  region  has  to  fight. 

The  insect  injures  both  the  roots  and  the  growing  parts  of  the  vine 
above  ground.  It  is  a  small  beetle,  about  one-fifth  of  an  inch  long,  and 
either  black  or  brown  in  color.     There  is  no  mistaking  its  identity  from 


*~\"\T^y^    \      J  s     '^1^^\ 

'v\1&$\\' **-■ -:  yj 

i            t       v 

W*ti 

r  "*^f 

FIG.  6.    Leaf  eaten  by  root  beetle. 

the  way  it  eats  out  chain-like  strips  from  the  leaf,  or  gouges  out  similar 
strips  on  the  shoots  and  other  growing  parts. 

Life  History. — The  adult  beetle  appears  in  May,  having  emerged  from 
the  ground  where  it  has  been  since  the  previous  year,  and  where  it  has 
passed  through  the  larval  and  pupal  stages.  It  begins  at  once  to  feed 
upon  the  leaves,  eating  out  narrow  slits  about  one-twentieth  of  an 
inch  wide  and  from  one-fourth  to  three-fourths  of  an  inch  long.  It 
attacks  the  shoots,  petioles,  pedicels,  and  to  a  less  extent  the  berry 
itself  in  the  same  way. 

After  feeding  for  a  couple  of  weeks,  egg-laying  begins.  The  eggs  are 
deposited  on  the  inner  bark,  or  in  crevices,  usually  beneath  two  or 
three  layers  of  the  old  bark.     Thev  are  laid  in  clusters  of  from  four  or 


IIS  UNIVERSITY  OF   CALIFORNIA EXPERIMENT   STATION. 

five  to  twenty-five  or  thirty.     Hatching  occurs  in  from  eight  to  twelve 

days,  when  the  young  larva  appears  and  crawls,  or  possibly  drops,  to 

the  ground  and  makes  its  way  to  the  roots. 

After  having  burrowed  its  way  through  the  ground  to  the  roots  it 

begins  feeding,   probably   mostly   on  the  smaller   roots   at  first,    later 

attacking  the  larger  ones  and  eat- 
ing out  strips  of  the  bark.  This 
feeding  continues  until  winter, 
when  the  larva  becomes  dormant, 
finally  changing  to  the  pupa  in  the 
following  spring.  Pupation  took 
place  this  year  during  the  last  of 
April,  and  continued  well  into  June. 
The  first  beetles  emerged  about  the 
first  of  May. 

The  most  serious   injury  to  the 
vine  is  due  to  the  work  of  the  larvae 

FIG.  7.    Imported  grape-root  worm.  ,-,  ,       n  „  ,       ,     • 

on  the  roots,  the  small  roots  being 
eaten  off  entirely,  thus  preventing  the  plant  foods,  taken  up  directly 
by  the  root  hairs,  from  reaching  the  growing  parts  of  the  vine.  The 
larger  roots  are  injured  by  having  strips  of  the  bark  eaten  off,  in  bad 
cases  of  injury  scarcely  any  of  the  bark  being  left.  Vines  thus  affected 
show  a  stunted  condition,  the  canes  failing  to  attain  a  normal  growth. 
and  in  severe  cases  the  vines  may  be  killed  outright. 

Control  Measures. — Since  the  insect  comes  to  the  surface  and  feeds 
upon  the  leaves  and  other  growing  parts  of  the  vine  an  opportunity  is 
offered  for  fighting  it  in  this  stage.  The  beetles  are  very  readily  jarred 
from  the  vine  and  may  be  captured  if  something  is  placed  under  the 
vines  in  which  they  can  be  caught. 

The  hopper  cage,  described  on  page  114,  checked  the  development  of 
the  beetles  in  a  vineyard  near  Lodi  during  the  past  season  This 
means  has  the  advantage  of  capturing  the  hoppers  also,  which  are  more 
than  likely  to  be  present,  at  the  same  time.  The  fact  that  the  beetles 
keep  emerging  from  the  ground  for  a  month  or  so  may  make  more  than 
one  Operation  necessary.  Fortunately,  however,  the  beetles  are  usually 
confined  to  a  limited  area  of  the  vineyard,  so  that  it  is  not  necessary  to 
go  over  a  Large  area.  When  the  beetles  alone  are  to  be  caught,  simply 
the  tray  on  the  bottom  of  the  cage  can  be  used.  Handles  may  be 
iched  directly  to  the  tray  for  convenience  in  manipulating. 

These    beetles   may   also  be   fairly   well  controlled  by   an  arsenical 

They  are  rather  resistant  to  poisons  and  a  strong  dose  must  be 

aged.     We  obtained  fairly  satisfactory  results  by  using  lead  arsenate 

in  the  ratio  of  five  pounds  to  fifty  gallons  of  water.     Paris  green  may 


Bulletin  192. 


INSECTS    INJURIOUS    TO    THE   VINE. 


119 


be  used  and  the  ratio  of  at  least  one  pound  to  one  hundred  gallons  of 
water  is  required.  This  spraying  should  be  done  as  soon  as  the  first 
beetles  make  their  appearance  in  the  spring. 

Since  the  pupae  are  within  four  to  eight  inches  of  the  surface  much 
good  can  be  done  by  thoroughly  stirring  the  ground  within  a  radius  of 
two  or  three  feet  about  the  vine  for  a  depth  of  six  inches  or  more.  If 
this  can  be  done  at  the  proper  time  when  they  are  in  the  pupal  stage 
it  will  no  doubt  destroy  many. 

It  has  been  suggested  and  some  experiments  seem  to  prove  that  if 
the  land  is  left  uncultivated  about  the  base  of  the  vine,  the  beetles  will 
be  unable  to  break  through  the  crust  at  the  surface.  We  have  not  had 
opportunity  to  demonstrate  this  point.  If  successful  it  must  depend 
largely  upon  a  type  of  soil  that  will  form  a  hard,  impenetrable  layer  at 
the  surface. 


HAWK  MOTH  LARVAE. 


These  larva?  are  occasionally  met  with  over  large  areas  every  year  in 
California,  and  in  certain  restricted  areas  they  sometimes  become 
exceedingly  abundant  and  may  completely  defoliate  a  vineyard.  The 
worst  case  that  has  come  to  our  notice  this  year  was  on  a  vineyard 
belonging  to  the  California  Wine  Association  near  Reedlev. 


FIG.  8.    Showing  one  vine  in  a  75-acre  vineyard  defoliated  by  Hawk  Moth  larvae. 


120 


IMYERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 


Here  seventy-five  acres  of  vines  were  completely  stripped  of   their 
foliage  and  scarcely  an  entire  leaf  was  left  on  the  area.     As  man] 
one  hundred  and  fifty  full-grown  larvae  were  counted  on  a  single  vine. 

In  this  case  the  owners   were  not  aware  of 
the  extent  of  the  danger  until  the  worms 
had  become  nearly  full  grown,  and  most  of 
the  damage  done.     At  this   time,  however 
a  gang  of  about  two  hundred  men 
to    work  picking  them  off  the   vines,  and 
worms  were  carried  away  by  the  cartloads 
and   burned.     The  species  concerned   here 
was    the    Achemon     Sphinx    {Philamjn 
achemon  Drury),  which   i>   tin-  most  com- 
mon   species    attacking    the    grapevine    in 
the  State. 

These  caterpillar-  may  b<-  found  on  the 
vines  late  in  May,  and  during  the  la 
part  of  June.  The  larvae  are  green  in  color, 
like  the  leaf,  and  are  therefore  not  readily 
distinguishable  when  they  are  small.  They 
soon  increase  in  size,  however,  and  their 
work  on  the  leaves  becomes  noticeable. 
While  small,  these  larv;e  may  be  distin- 
guished by  a  large  horn  on  the  posterior 
end  of  the  body,  but  this  is  lost  during  a  molt  before  they  are  quite 
full  grown. 


FIG.  9.     Hawk    Moth    larva. 
(Philantpeies  achemon  Drury.) 


Life  History. — These  insects  hibernate  in  the  pupa  or  chrysalis  stag* 
and  while  in  the  ground  may  be  distinguished  as  large  cylindrical 
objects  of  a  dark  brown  color  (Fig.  10).  About  the  middle  of  May  or 
thereabouts  they  emerge  from  these  chrysalids  in  the  ground  as  large 
and  handsome  moths  (Fig.  11).  These  are  the  common  moths  that 
poise  over  flowers  at  dusk.  They  are  particularly  attracted  by 
petunias,  and  it  has  been  suggested  that  they  might  he  captured  in 
large  numbers  about  these  flowers. 

The  eggs  are  laid  on  the  vine,  and  the  larvae,  upon  hatching,  begin 
immediately  to  feed  upon  the  grape  foliage.  Since  they  arc  voracious 
feeders  and  grow  to  a  very  large  size,  three  inches  long  or  more,  they 
consume  an  enormous  quantity  of  leaves.  This  year  most  of  the  larvae 
-  mature  by  the  twentieth  of  June.  When  mature  they  repair  to 
the  ground,  where  they  pupate.  In  the  vineyard  already  mentioned. 
there  appeared  a  second  brood  of  caterpillars  during  the  middle  of 
July.  None  of  these  reached  their  full  growth,  dying  from  some 
unknown   cause  while  they  were  but  an  inch  and  a  half  long.     Thev 


Bulletin  192. 


INSECTS    INJURIOUS    TO    THE   VINE. 


121 


had  all  disappeared  when  we  visited  the  vineyard  on  August  the  first, 
and  according  to  the  owners  they  simply  dried  up.  It  was  probably 
due  to  a  fungous 
disease  which  often 
destroys  these  cat- 
erpillars in  great 
numbers.  We  also 
found  these  cater- 
pillars in  the  vine- 
yards about  Lodi  in 
June  and  August, 
indicating  that 
there  are  two 
broods  in  a  season. 

Control  Measures. 
Where  there  are 
but  occasional 
specimens  of  thi's 
insect  found  in  the 
vineyard,  the 
cheapest  and  most 
practical  way  is  to 
pick   them    off    by 

hand.    W  here  there         FIG  10     Chrysalids  of  a  Hawk  Moth  (Philampeles  achemon  Drury). 

are  immense  num- 
bers   of  them,   as  in  the  case  mentioned  at    Reedley,    hand   picking 
becomes  a  laborious  task.     In  the  latter  case  a  thorough  spraying  with 

a  strong  arsenical 
spray  applied  just 
at  the  time  they 
are  hatching,  will 
check  them  before 
they  can  do  a  great 
deal  of  harm. 

If  the  adult 
moths  are  particu- 
larly attracted  by 
the  petunias,  as 
seems  to  be  the 
case,  a  means  of 
capturing  them  in 
this  stage  may  be 
found  in  poisoning  the  flowers  thoroughly  with  some  soluble  poison  or 
by  catching  them  in  traps.     The  effectiveness  of  these   methods   will 


FIG.  11.    Hawk  moth  (Philampeles  achemon  Drury). 


L22 


UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 


depend  upon  whether  many  of  the  eggs  are  deposited  before  they  fly 
about  much.  While  numbers  of  moths  may  be  caught  in  this  way. 
it  is  doubtful  if  it  will  ever  prove  of  very  great  practical  value. 


GRASSHOPPERS. 


These  insects  do  a  great  deal  of  injury  to  vines  every  year  in  some 
parts  of  the  State.  This  year  they  have  been  abundant  everywhere 
and  considerable  damage  has  resulted.  In  a  vineyard  twelve  miles 
east  of  Fresno  forty  or  fifty  acres  of  vines  were  completely  defoliated. 
These  insects  are  generally  most  troublesome  in  new  vineyard  sections 
or  localities  surrounded  by  large  areas  of  uncultivated  land. 


FIG,  12.    Vineyard  defoliated  by  grasshoppers. 

ZAfi  History. — The  eggs  of  the  grasshoppers  are  laid  in  the  ground 
in  the  late  summer  or  fall,  and  a  decided  preference  is  shown  for  uncul- 
tivated land.  These  eggs  are  laid  in  capsules  containing  a  large  num- 
ber, and  are  protected  by  a  frothy  or  gummy  substance  which  prevents 
them  iron,  being  affected  by  unusual  weather  conditions.  The  eggs 
remain  in  the  ground  during  the  winter  and  hatch  the  following  spring. 
The  young  grasshopper  is  similar  in  appearance  to  the  adult,  except 
that  the  winge  are  Lacking,  but  these  are  gradually  acquired  with  molt- 
ing. There  is  usually  but  a  single  generation,  though  in  some  parts  of 
I  here  are  probably  two. 


Bulletin  192. 


INSECTS    INJURIOUS    TO    THE    VINE. 


123 


FIG.  13.    Valley  grasshopper  (CEdaleonotus  enigma). 


Control  Measures. — Grass- 
hoppers may  be  controlled 
by  poisoned  bait,  by  spray- 
ing heavily  a  few  rows  along 
the  border  of  a  field,  by  the 
hopper  dozer,  by  burning 
waste  feeding  areas,  and  by 
the  introduction  of  turkeys. 
Various  combinations  of  two 
or  more  of  these  measures 
may  be  used  to  fit  particular 
cases.     Of  the  methods  used 

to  protect  vineyards,  poisoned  bait  is  probably  the  most  common.     This 
consists  of  bran  and  molasses  or  other  sweet  substance  poisoned  with 

arsenic  and  distributed  in 
handfuls  about  the  vine.  The 
proportions  are  as  follows: 
forty  pounds  of  bran,  two  gal- 
lons of  cheap  molasses,  and 
five  pounds  of  arsenic.  Cheap 
glycerine  may  be  used  to  pre- 
vent the  mixture  from  drying. 
If  the  grasshoppers  are  enter- 
ing in  well-defined  swarms 
and  caught  on  the  first  few 
rows  they  may  be  killed  by 
heavily  poisoning  a  few  rows  on  the  side  at  which  they  are  entering. 
Some  growers  find  turkeys  to  be  the  most  successful  destroyers,  and  if 
the  hoppers  are  not  too  abundant,  this  method  is  probably  as  good  as 
any   particularly  at  a  time  when  the  hoppers  are  still  small. 


JfSS^ 

{  '" 

FIG.  14.    Differential  grasshopper  (Melanoplus 
differ  entialis).     Young. 


FIG.  15.    Differential  grasshopper  (Menanoplus  differ  entialis).    Adult. 


124 


UNIVERSITY   OF   CALIFORNIA — EXPERIMENT   STATION. 


Those  who  have  been  most  successful  with  turkeys  go  about  using 
them  in  a  systematic  way.  They  turn  in  a  band  of  them  early  in  the 
morning  and  let  them  feed  for  a  couple  of  hours,  then  drive  them  into 
a  cool  barn  where  they  remain  through  the  heat  of  the  day.  In  the 
evening  they  are  again  turned  into  the  vineyard  for  two  or  three  hours 
and  again  confined  in  an  inclosure,  so  that  they  obtain  a  straight  grass- 
hopper diet  supplemented  by  gravel,  to  which  they  have  access  while 
not  in  the  vineyard. 

When  vineyards  adjoin,  or  are  near,  large  uncultivated  tracts,  where 
the  grasshoppers  hatch  out  in  large  numbers,  it  is  best  to  look  beyond 
the  vineyard  in  planning  the  control.  This  may  mean  more  or  less 
organized  effort  in  burning  off  or  plowing  such  uncultivated  lands. 
For  a  full  account  of  this  and  other  methods  of  grasshopper  control 
the  reader  is  referred  to  Bulletins  Nos.  142  and  170  of  this  Station. 


CUT  WORMS  AND  ARMY  WORMS. 

These  are  the  larvae  of  Noctuid  moths,  which  often  become  abundant 

over  limited  areas  and  do  much  damage  to  vines. 

Cut  worms  and  Army  worms  are  terms  applied  to  the  same  insects  in 

California.  In  ordinary  years  they 
are  not  present  in  sufficient  numbers 
to  cause  much  concern,  and  in  such 
years  they  are  known  simply  as  cut 
worms.  When  all  conditions  are 
favorable,  however,  certain  species 
develop  in  enormous  numbers  and 
having  exhausted  the  food  supply 
where  they  ; breed,  they  begin  to 
migrate  or  march,,  commonly  in  a 
definite  direction,  as  an  army  in 
search  of  new  food.  When  they  thus 
appear  in  such  large  numbers  and 
take  on  the  migrating  habit  they  are 
called  army  worms. 

Some  of  the  caterpillars  have  the 
habit  of  climbing  up  vines  and 
trees  and  eating  off  the  buds  in 
the  early  spring.     These  are  called 

climbing  cut  worms.     Others    remain   at  or   near  the  surface  of    the 
ind  and  feed  by  cutting  off  the  plants  at  this  point.     They  are  more 

commonly  found   in    the  grass    hinds,  but  very  frequently  attack  culti- 


Y\(,.    16.      Army      worm      (Heliophila     "///- 
pun  species  I  hal  wrae  abundanl 

Lodi  thifi  y  i 


Bulletin  192. 


INSECTS    INJURIOUS    TO    THE   VINE. 


125 


vated  crops,  particularly  on  land  that  was  in  grass  the  previous  year. 
It  is  the  two  former— the  climbing  cut  worms  and  army  worms -that 
chiefly  concern  growers  of  vines. 

The  climbing  cut  worms  appear  in  the  early  spring  and  eat  off  the 
expanding  buds.  They  also  feed  upon  the  young  leaves  as  they  appear, 
but  an  early  attack  on  the  swelling  buds  is  when  the  most  serious 
damage  is  done,  because  the  removal  of  the  principal  bud  destroys  the 
fruit  and  the  later  buds  usually  produce  sterile  shoots.  The  two 
commonest  species  concerned  here  are  Paragrotis  messoria  Harris  and 
Peridroma  margaritosa  sauci  Hubn. 

The  life  history  of  all  the  species  of  this  group  is  much   the  same, 


FIG    17.     Moths  of  cut  worms. 

and  they  may  be  discussed  together.  The  majority  spend  the  winter 
as  a  partly  grown  larva.  In  the  spring  they  again  become  active  and 
begin  to  feed  after  being  more  or  less  dormant  during  the  winter.  If 
they  are  the  climbing  species  they  may  be  found  attacking  the  buds  or 
young  leaves  of  the  vine.'  When  they  become  full-grown  larvae  they  go 
to  the  ground,  where  they  change  to  pupae.  After  two  or  three  weeks 
in  this  stage  the  adult  moth  appears.  These  are  usually  dark  colored 
(Fig.  17),  and  because  they  fly  about  at  night  are  seldom  seen. 

The  eggs  are  laid  mostly  on  the  stems  of  grasses  near  the  ground. 
The  larvae  hatching  from  these  feed  at  or  near  the  ground,  and  since 
they  work  mostly  at  night  are  not  readily  seen  in  their  concealed  situa- 
tions during  the  day.  There  being  plenty  of  vegetation  at  this  season 
also  they  do  not  interfere  seriously  with  the  crop.     By  fall  they  become 


126  UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 

partly  grown  and  spend  the  winter  in  a  more  or  less  dormant  condi- 
tion. There  are  generally  two  broods  of  the  worms  in  California  and 
in  some  eases  probably  three.  Any  one  of  several  species,  however,  may 
increase  to  immense  numbers,  and  they  are  then  called  army  worms. 

They  appear  in  large  numbers  as  army  worms,  generally  wuth  the 
second  brood  in  midsummer.  During  the  past  year  in  the  vicinity  of 
Lodi  there  was  a  distinct  outbreak  of  army  worms  appearing  simulta- 
neously in  a  dozen  or  more  different  places.  In  nearly  every  case  these 
came  from  grain  fields  in  which  they  bred,  and  because  of  the  large 
numbers  and  scarcity  of  food  were  forced  to  migrate,  and  as  a  result. 
a  number  of  vineyards  were  threatened  wuth  defoliation.  These  grain 
fields  or  breeding  places  become  pretty  well  dried  up  by  August,  and 
furnish  very  little  succulent  growth  for  the  voracious  army  worm. 

The  worms  appeared  this  year  during  the  first  w7eek  in  August.  They 
had  been  feeding  for  a  week  or  two  in  the  grain  fields,  since  some  were 
nearly  full  grown,  but  had  not  been  observed  to  migrate  until  the  date 
mentioned.  In  one  of  these  grain  fields  a  contagious  bacterial  disease 
killed  them  off  by  the  thousands,  and  very  effectively  checked  their 
progress.  Portions  of  a  number  of  young  vineyards  were  defoliated 
before  their  presence  was  realized.  The  species  concerned  here  was  the 
true  army  worm  of  the  Eastern  States,  which  bears  the  scientific  name 
of  Heliophila  unipuncta.  In  bearing  vineyards,  besides  eating  off  the 
leaves,  these  worms  have  the  pernicious  habit  of  cutting  off  the  stems 
of  the  clusters  of  fruit,  which  drop  to  the  ground  and  dry  up.  In  a 
portion  of  a  bearing  vineyard  near  Lodi,  wThere  these  pests  were  present, 
this  unripe  fruit  was  picked  up,  while  still  fresh,  by  the  basketfuls  and 
made  into  jelly. 

These  caterpillars  are  mostly  dull-colored  worms  from  one  to  two 
inches  long,  with  longitudinal  strips  of  black,  gray  and  yellow  or  red- 
dish brown.  There  is  considerable  variation  in  color  in  the  same 
species,  some  being  much  darker  in  color.  Generally  the  midsummer 
brood  from  which  the  army  worms  arise  are  darker  colored  than  the 
-pring  brood.  The  one  present  in  Lodi  and  vicinity  this  year  (see  Fig. 
16)  had  a  broad  black  velvety  stripe  on  the  dorsal  side.  Below  this 
was  a  stripe  of  whitish  yellow  about  one  half  the  width  of  the  former,. 
with  its  center  made  up  of  broken  wavy  lines.  BelowT  this  was  another 
narrow  stripe  of  black  with  the  spiracles  on  the  lower  edge;  back  and  a 
little  above  each  spiracle  was  a  conspicuous  white  spot  that  on  first 
sight  would  be  taken  for  the  spiracles  themselves.  Below  this  is  another 
-tripe  of  light  brown,  and  on  the  ventral  surface  a  general  color  of 
cinnamon  brown. 

Control  Measures. — The  cut  worm,  although  belonging  to  the  same 
group  as  the  army  worm,  on  account  of  the  difference  in  habits  must 
be  controlled  in  a  different  way.     Since  it  is  those  species  which  acquire 


Bulletin  192.  INSECTS  INJURIOUS  TO  THE  VINE.  127 

the  climbing  habit  that  attack  vines,  they  require  a  different  manner 
of  treatment  from  those  which  feed  upon  plants  at  or  near  the  surface. 
Because  they  actually  devour  the  buds  of  the  vine,  the  application  of 
a  poison  spray  ought  to  be  effective.  However,  since  the  surface  on 
which  there  may  be  poison  in  the  case  of  buds  is  so  small,  one  worm 
may  destroy  most  of  the  buds  on  an  ordinary-sized  vine  before  the  dose 
eaten  will  prove  fatal.  Probably  one  of  the  best  ways  of  fighting  these 
is  to  place  poisoned  bait  around  the  base  of  the  vine.  (For  the  ingre- 
dients see  under  Grasshoppers,  page  123.)  This  will  be  eaten  by  the 
worms  in  preference  to  climbing  up  the  vines  and  destroying  the  buds. 
They  may  also  be  captured  by  means  of  traps.  Because  of  their  habit 
of  feeding  at  night  and  remaining  concealed  during  the  day,  pieces  of 
boards  may  be  placed  on  the  ground  around  the  vine  and  these  may  be 
turned  over  during  the  day  and  the  worms  killed. 

In  case  of  outbreaks  of  army  worms  the  most  important  and  success- 
ful means  of  fighting  them-  is  to  keep  them  out  of  the  vineyards 
entirely.  This  can  be  successfully  done  if  they  are  discovered  in  time, 
or  if  already  in  one  portion  they  can  be  kept  from  spreading  over  the 
rest  of  the  vineyard.  They  travel  in  immense  numbers  in  a  definite 
direction,  coming  generally  from  an  adjoining  or  nearby  grain  field.  If 
a  furrow  is  plowed  along  the  side  of  the  vineyard  to  be  protected  it  will 
effectively  stop  their  progress.  This  furrow  should  be  plowed  as  deep 
as  possible,  with  the  vertical  side  next  to  the  field  to  be  protected.  It 
can  be  further  trimmed  with  a  spade,  preferably  cutting  under  slightly, 
making  a  smooth  surface,  over  which  few,  if  any,  of  the  worms  will 
make  their  way.  Above  this  shoulder  fine  pulverized  earth  should 
slope  as  abruptly  upward  as  possible.  If  any  of  the  worms  succeed  in 
climbing  up  over  the  smooth  surface  made  by  the  spade  they  will  be 
pretty  sure  to  fall  back  as  they  reach  this  fine  loose  earth  in  an  attempt 
to  ascend  over  the  projecting  shoulder.  Postholes  should  be  dug  on 
the  straight  edge  of  the  furrow  every  fifteen  or  twenty  feet.  The  worms 
in  failing  to  scale  the  vertical  side  of  the  furrow  will  crawl  along  in  the 
bottom  and  fall  into  these  holes.  Here  they  may  be  killed  by  pouring 
in  a  little  crude  oil,  or  by  pouring  in  a  little  distillate  and  dropping  in 
a  match,  thus  burning  them,  or  the  holes  filled  in  and  others  dug.  They 
may  also  be  killed  in  the  furrow  by  sprinkling  them  with  kerosene  or 
by  pouring  a  strip  of  crude  oil  along  the  furrow. 

It  is  most  essential  in  fighting  army  worms  that  prompt  and  vigorous 
efforts  be  undertaken  immediately,  since  a  day's  delay  may  mean  con- 
siderable loss  and  more  difficulty  in  handling  the  situation.  Once  they 
are  in  the  vineyard  the  vines  infested  should  be  heavily  sprayed  with 
lead  arsenate  at  the  rate  of  five  pounds  to  fifty  gallons  of  water,  or 
with  paris  green  in  the  proportion  of  one  pound  to  seventy-five  or  one 
hundred  gallons  of  water.     In  addition  to  this  the  furrow  should  be 


L28  UNIVERSITY   OF   CALIFORNIA EXPERIMENT    STATION. 

plowed,  as  already  described,  beyond  the  infested  portion  to  check  their 
further  spread.  If  these  measures  are  undertaken  promptly,  what 
might  be  a  serious  loss  can  be  averted. 


FLEA  BEETLES. 

(Haltica  sps.) 

These  beetles  have  generally  been  confused  with  the  root  beetle 
already  discussed  in  this  bulletin.  In.  these  beetles  the  thighs  of  the 
hind  legs  are  enlarged,  thus  enabling  the  insect  to  jump  much  in  the 
same  way  as  the  flea;  hence  the  name.  They  have  frequently  been 
reported  as  doing  damage  in  the  State,  but  during  the  past  season  we 
have  not  learned  of  any  important  injury  done  by  them.  Two  or  three 
specimens  were  taken  near-Lodi,  and  while  no  particular  effort  was 
made  to  collect  them,  this  was  all  we  obtained  during  the  season. 
Certainly  there  were  no  large  numbers  of  these  beetles  in  the  sections 
where  our  work  was  carried  on  this  past  year.  Several  growers  reported 
that  the  flea  beetle  was  doing  considerable  damage,  but  upon  inv 
gation  these  were  found  to  be  the  root  beetle.  They  are  said  to  be 
particularly  abundant  in  the  Sonoma  Valley,  but  we  did  not  have  the 
opportunity  of  visiting  the  valley  during  the  present  season.  There 
are  about  a  dozen  species  of  the  genus  Haltica  occurring  in  this  State. 
probably  the  commonest  occurring  on  the  vine  being  the  species  bimar- 
ginata.  This  species  is  not  confined  to  the  grape  alone,  and  during  the 
past  year  it  was  exceedingly  abundant  in  many  places  over  the  State 
on  the  alder.  The  grape  flea  beetle  of  the  Eastern  States  (Haltica 
chalybia)  is  not  known  to  occur  here. 

The  flea  beetle  on  the  grape  is  commonly  of  a  bluish  color,  about  one- 
fifth  of  an  inch  in  length,  and  is  capable  of  jumping,  while  the  root 
beetle  is  either  black  or  brown  in  color  and  has  no  power  to  jump.  The 
injuries  of  these  two  beetles  are  also  readily  distinguishable.  The  flea 
beetle  eats  out  irregular  holes,  which  may  differ  much  in  size  and  shape, 
while  the  root  beetle  eats  out  narrow  strips  of  very  uniform  size  and 
shape.     They  also  present  entirely  different  life  histories. 

Life  History. — The  flea  beetle  passes  the  winter  among  leaves  or  in 
other  situations  affording  some  protection  to  the  adult  beetle,  and 
In  the  early  spring  and  feeds  upon  the  buds  of  the  vine.  These 
may  be  entirely  eaten  away  or  the  centers  gouged  out,  thus  destroying 
the  bud-.  After  feeding  for  some  time  they  begin  depositing  their 
__-  gi  tierally  in  the  cracks  in  the  bark  or  at  the  base  of  the  buds. 
Th<  larvae,  after  hatching  out,  attack  the  leaves  and  eat  out  holes,  as 
already  indicated.     They  continue  to  feed  as  larva?  for  three  or  four 


Bulletin  192.  INSECTS  INJURIOUS  TO  THE  VINE.  129 

weeks,  when  they  drop  to  the  ground,  make  a  little  cell  just  beneath 
the  surface,  and  change  to  pupae.  The  beetles  emerge  a  week  or  two 
later  and  these  feed  upon  the  leaves.  There  are  probably  two  genera- 
tions of  the  insect  each  year.  Those  we  obtained  were  taken  as  adult 
beetles  in  June,  which  were  from  eggs  laid  in  the  early  spring,  but 
whether  these  remain  until  winter  and  hibernate,  or  again  lay  eggs, 
was  not  determined.  t 

Control  Measures. — Since  this  insect  feeds  upon  the  foliage  both  as 
larva  and  adult,  it  may  be  controlled  by  means  of  a  poison  spray,  either 
paris  green  or  lead  arsenate.  The  beetles  are  also  easily  jarred  from  the 
vines  and  the  method  described  for  capturing  the  root  beetle  can  be 
used  here. 


THE  GRAPE-LEAF  FOLDER. 

(Desmia  funeralis  Huber.) 

This  insect  occurs  in  considerable  numbers  in  some  sections  of  the 
State  every  year,  but  the  total  injury  is  not  usually  very  great.  During 
the  past  season  the  worst  attack  that  came  to  our  notice  was  in  a  vine- 
yard near  Reedley,  where  seventy-five  or  one  hundred  acres  of  vines 
had  a  large  number  of  their  leaves  rolled.  On  some  vines  nearly  every 
leaf  was  found  to  be  rolled  and  harboring  the  larvae  of  this  insect. 
Occasional  specimens  were  also  found  near  Lodi,  but  they  were  not 
numerous  enough  to  do  any  important  injury. 

They  may  be  easily  detected  in  a  vineyard  by  the  characteristic 
rolling  of  the  leaves.  One  edge  is  rolled  up  rather  tightly  to  about  half 
way  across  the  leaf,  making  a  tube  less  than  the  diameter  of  a  lead 
pencil,  in  which  the  larva  lives.  The  leaf  is  always  rolled  on  the  under 
side.  The  insects  feed  by  eating  off  the  free  edge  of  the  leaf  in  the  interior 
of  the  roll,  so  that  they  are  always  protected  by  the  outer  layers  of  the 
rolled  portion.  The  insect  hibernates  as  a  chrysalis,  appearing  and 
laying  eggs  upon  the  vine  in  the  spring.  The  larvae  of  the  first  brood 
appear  about  the  first  of  June.  By  the  twentieth  of  June  at  Reedley 
this  year  the  larvae  had  all  changed  to  pupae.  The  larva  is  a  greenish- 
white  caterpillar,  about  an  inch  long  when  full  grown.  They  wriggle 
out  of  their  nests  very  vigorously  when  disturbed  and  drop  to  the 
ground.  *Larvae  were  taken  at  Lodi  in  June  and  August,  indicating 
that  there  are  at  least  two  broods  in  a  season. 

*  The  head  and  prothoracic  shield  are  light  brown  in  color.  On  the  mesothoracic 
segment  are  two  pale-brown  spots  or  rings,  and  beyond  these  laterally  are  two  larger 
and  darker  crescent-shaped  spots.  There  is  also  a  pale  spot  on  the  same  segment  more' 
ventrally  and  a  little  forward.  On  the  preceding  segment  are  two  large  irregular  pale- 
brown  spots  and  one  small  round  spot,  also  of  pale  brown.  On  the  penultimate 
segment  there  are  two  dark  crescent-shaped  spots  situated  dorsally. 

3— Bul.  192 


Bulletin  192. 


INSECTS    INJURIOUS    TO    THE   VINE. 


131 


This  insect  occurs,  apparently,  throughout  the  United  States.     It  is 
very  common  in  the  Eastern  and  Middle  Western  States,  but  there  is 


FIG.  19.    Larva  of  grape  leaf-roller. 


a  striking  difference  in  habits  between  the  insect  there   and   what  is 
considered  the  same  species  here.     In  the  East,  the  leaf  is  simply  folded 


FIG.  20.    Moth  of  grape  leaf-roller,  enlarged. 


over  on  the  upper  surface  and  the  edges  sewed  down  by  strands  of  silk. 
There  the  larva  feeds  by  eating  off  the  upper  surface  of  the  leaf,  thus 
skeletonizing  it.     Here  the  leaf  is  very  distinctly  rolled  and  instead  of 


132  UNIVERSITY   OF   CALIFORNIA — EXPERIMENT   STATION. 

eating  off  the  upper  surface  it  feeds  on  the  free  edge.  According  to  its 
habits  in  this  State,  leaf-roller  would  be  a  more  appropriate  name  than 
leaf-folder.  Specimens  of  the  moth  sent  to  the  Bureau  of  Entomology 
at  Washington,  D.  C,  were  identified  by  Dr.  Dyar  as  Desmia  funeralis 
Huber — the  same  species  that  occurs  in  the  Eastern  States. 

The  moth  is  nearly  an  inch  across  the  expanded  wings,  and  is  black 
with  white  markings.  There  are  two  white  spots  on  each  wing,  those 
on  the  posterior  wings  being  larger,  and  in  some  specimens  fusing  into 
a  single  large  spot.  There  are  also  two  white  bands  across  the  abdomen, 
one  about  the  center  and  one  near  the  tip.  The  wings  are  also  bordered 
with  a  fringe  of  white,  and  the  tarsi  and  apical  half  of  the  antennae 
are  white. 

Control  Measure. — The  only  control  measure  which  is  likely  to 
prove  effective  is  to  spray  with  an  arsenical  before  the  rolling  of  the 
leaf  is  commenced,  so  that  they  may  be  obliged  to  eat  the  poison,  even 
though  they  are  within  the  rolled  portion.  If  they  are  not  too  abundant, 
hand  picking  or  simply  crushing  the  folded  portion  of  the  leaves  will 
be  the  most  practical. 


LEAF  CHAFERS. 


Under  this  head  come  the  rose  chafer,  and  other  allied  species,  which 
often  attack  the  leaves  of  the  grapevine.  The  true  rose  chafer,  which 
often  does  much  injury  to  vines  in  the  Eastern  States,  as  far  as  we  are 
aware,  does  not  occur  in  California. 

A  species  which  was  very  abundant  in  the  neighborhood  of  Florin 
during  the  past  season  was  Serica  mixta  Lee.  This  insect  was  not 
restricted  in  its  feeding,  however,  to  the  vine,  but  attacked  a  great 
variety  of  plants.  Hoplia  sackonii  has  also  been  taken  in  large  num- 
bers on  vines  at  Fresno. 

The  life  history  of  the  rose  chafer  has  been  carefully  studied,  and  the 
life  history  of  these  allied  species  may  be  much  the  same.  The  younger 
>s  of  these  insects  are  passed  in  the  ground,  where  the  larva?  feed 
upon  the  roots  of  plants,  preferably  grasses.  They  are  full  grown  by 
fall  and  in  the  spring  ascend  toward  the  surface,  where  they  change  to 
pupae.  Two  or  three  weeks  later  they  emerge  from  the  ground  as  adult 
beetles  and  attack  the  grape  and  other  plants.  A  sandy  soil  is  especially 
adapted  for  their  underground  habits.  After  feeding  as  adult  beeths 
f  >r  two  or  three  weeks  they  deposit  their  eggs  in  the  ground  and  from 
these  the  next  generation  of  larvae  emerge  and  feed  upon  the  roots  until 
fall 

Control  Men, lire — These  insects  are  rather  difficult  to  control,  but  a 
liberal   dose  of  poison  will  check  them  if  they  are  not  present  in  great 


Bulletin  192. 


INSECTS    INJURIOUS    TO    THE   VINE. 


133 


swarms,  as  they  sometimes  occur.     The  jarring  method  as  described  for 
the  root  beetle  will  also  prove  valuable. 

Since  these  insects  feed  in  the  larval  state  upon  the  roots  of  grasses 
growing  along  the  roadsides  or  fences  or  irrigation  ditches,  much  can  be 
done  to  prevent  an  outbreak  by  keeping  nuch  places  free  from  vegetation. 


WIRE  WORMS. 

These  are  long  cylindrical  worms  with  a  dark 
brown  leathery  covering  resembling  somewhat  a 
piece  of  rusty  wire.  They  live  for  a  year  or 
more  in  the  ground,  feeding  upon  the  roots  of 
plants.  They  feed  upon  a  variety  of  plants  and 
are  not  restricted  to  grape  roots  alone.  We 
have  taken  as  many  as  fourteen  of  these  worms 
from  around  the  roots  of  a  vine  from 
a  foot  and  a  foot  and  a  half  from  the 
surface.  During  the  growing  season  of 
the  vine  when  the  vineyard  is  free 
from  vegetation  these  wire  worms  must 
feed  to  a  considerable  extent  upon  the 
roots  of  the  vine.  The  adult  is  the  well- 
known  click  or  snapping  beetle,  the  one 
most  commonly  met  with  being  about 
one-half  an  inch  long,  slender,  and  of 
a  dark  brown  or  black  color.  We  have 
seen  immense  swarms  of  these  click 
beetles  in  a  vineyard  near  Hanford, 
and  when  they  occur  in  such  large 
numbers  they  probably  do  considerable  injury 
to  the  vine  as  root  feeders. 

When  young  vines  are  planted  in  soil  which 
has  previously  been  in  hay  or  pasture  the  wire 
worms  may  attack  the  bark  just  below  the  sur- 
face and  kill  the  vine  by  girdling  it.  Rupestris 
St.  George  seems  particularly  susceptible  to  this 
form  of  attack.  The  vines  may  be  saved  if  the 
wire  worms  congregated  around  the  collar  of  the 
vine  one  or  two  inches  below  the  surface  are 
collected  by  hand  in  time. 

Treatment. — We  know  of  no  generally  satisfac- 
tory remedy  for  these  insects.  Turning  up  the 
soil  is  recommended  for  the  same  insect  in  the 


FIG.  21.  A 
wire  worm. 


FIG.  22.     Young  vine  gir- 
dled by  wire  worms. 


134 


UNIVERSITY    OF   CALIFORNIA — EXPERIMENT   STATION. 


Eastj  especially  in  the  fall  or  winter,  but  such  an  operation  is  likely  to 
prove  of  little  value  in  our  climate  here.  Besides,  most  of  those  found 
around  the  vines  were  below  the  reach  of  any  plow.  Clean  culture  in 
the  vineyard  will  do  as  much  as  anything,  since  ordinarily  they  feed 
upon  the  roots  of  grasses  and  other  plants  at  a  comparatively  short 
distance  from  the  surface. 


ERINOSE.* 

Erinose  is  a  disease  of  the  vine  characterized  by  swellings  on  the 
upper  surface  of    the    leaves,   and    corresponding   depressions  on  the 

lower  surface.     These  swell- 
i'l  ings,  when  numerous,  cause 

!■  considerable  deformation  of 

the  leaves,  but  not  the  change 
of  color  to  yellow  or  brown 
which  is  characteristic  of 
most  fungous  diseases.  Even 
very  badly  affected  leaves 
retain  almost  their  normal 
green  color  on  the  upper  sur- 
face until  late  in  the  season. 
The  depressions  on  the 
under  side  are  coated  with  a 
thick  felt-like  covering, 
which,  at  first  pure  white, 
gradually  turns  rusty  and 
finally  becomes  dark  brown. 
Generally,  the  swellings  and 
corresponding  depressions 
are  isolated  and  few  in  num- 
ber on  the  affected  leaves,  but  in  severe  cases  they  are  numerous  enough 
to  become  confluent  and  the  whole  lower  surface  is  then  completely 
hidden  by  the  felt-like  covering.  Occasionally,  indeed,  the  felt-like 
material  extends  to  the  upper  surface  in  narrow  strips  bordering  the 
veins,  and  may  even  be  found  on  the  petioles  and  flower  clusters. 

Most  of  the  specimens  received  at  the  laboratory  are  sent  under  the 
impression  that  they  are  attacked  by  a  fungus,  and,  in  fact,  the  coating 
has  a  strong  superficial  resemblance  to  some  fungous  growths.  A  micro- 
acopic  examination  shows,  however,  that  it  consists  of  a  mass  of  hyper- 
trophic! hai r~  or  abnormal  outgrowths  of  the  epidermal  cells  of  the 
Leaf.     They  are  larger,  more  abundant,  and  more  persistent  than  the 

l;«  .  Lsed  from  Bulletin  No.  L36,  by  F.  T.  Bioletti  and  E.  H.  Twight. 


FIG.  23.  Vine  leaf  affected  with  Erinose— upper  surface. 


Bulletin  192.  INSECTS  INJURIOUS  TO  THE  VINE.  135 

normal  leaf-hairs  of  the  leaf,  and  differ  also  in  being  often  branched 
and  usually  unicellular.  This  abnormal  growth,  in  common  with 
similar  growths  found  on  other  plants,  is  called  an  erineum,  from  a 
Greek  word  meaning  woolly.  This  is  the  derivation  of  the  word  erinose, 
which  means  woolly  disease — a  very  appropriate  name.  The  erinea  of 
leaves  were  formerly  supposed  to  be  of  fungous  origin,  but  are  now 
known  to  be  due  to  the  attacks  of  minute  mites.  The  feeding  of  these 
mites  exert  a  stimulating  effect  upon  the  epidermal  cells  of  the  leaf, 
which  causes  them  to  grow  out  into  the  abnormal  hair-like  processes 
already  described.  The  mite  causing  erinose  of  the  vine  is  known  as 
Eriophyes  vitis,  and  is  related  to  the  mites  causing  a  similar  disease  of 
the  walnut  and  the  leaf  blister  of  the  pear,  both  of  which  are  very 
common  in  California. 

The  Eriophyes  vitis  is  not  a  true  insect,  but  a  mite  or  acarid  belong- 
ing to  the  class  of  Arachnida  to  which  belong  also  spiders,  scorpions, 
ticks,  and  our  common  red  spider  so  destructive  to  fruit  trees.  These 
mites  are  extremely  minute,  and  only  a  practiced  eye  can  perceive  them 
among  the  tangled  mass  of  erineum  on  the  leaf,  by  the  aid  of  an  ordinary 
hand  magnifier,  and  then  only  with  great  difficulty. 

Amount  of  Injury. — Erinose  was  formerly  considered  to  be  a  very 
serious  disease  of  the  vine,  owing  to  the  fact  that  its  effects  were  con- 
fused with  those  of  the  powdery  mildew.  It  is  only  in  very  exceptional 
cases  that  it  is,  alone,  capable  of  doing  serious  injury  to  the  vine  or  its 
crop.  When  accompanying  oidium  or  drought  it  may,  however,  per- 
ceptibly increase  the  damage  due  to  these  causes.  When  very  abundant 
it  may  seriously  interfere  with  the  growth  of  young  vines,  but  accord- 
ing to  Mayet,  never  damages  old  vines,  except  by  interfering  slightly 
with  the  ripening  of  the  canes,  or  at  most  causing  an  almost  impercep- 
tible diminution  of  crop.  All  varieties  of  vines  are  not  equally  attacked. 
According  to  Ravaz,  certain  American  species  such  as  Berlandieri, 
Mustang,  Cinerea,  Cordifolia,  and  Scuppernong  are  immune.  All  vari- 
eties of  Vinifera  are  susceptible,  but  not  equally.  Of  varieties  culti- 
vated in  California,  Sauvignon,  Sirah,  Marsanne,  and  Gamay  Teinturier 
are  said  by  Ravaz  to  be  little  subject  to  attack;  while  Aramon,  Cinsaut, 
and  Frontignan  (Small  Muscatel)  are  very  susceptible.  The  worst 
cases  so  far  observed  in  California  have  been  on  Flame  Tokay  and 
Mission,  but  it  has  been  found  also  on  other  varieties,  among  them 
Zinfandel  and  Muscat. 

Distribution  in  California. — The  first  specimens  of  erinose  received 
by  the  Experiment  Station  were  sent  from  Windsor,  Sonoma  County, 
in  1896.  The  next  year  affected  leaves  were  received  from  Healdsburg 
and  Dry  Creek,  in  the  same  county.  All  these  cases  were  upon  Mission 
vines.  Since  then  specimens  of  the  disease  have  been  received  from 
nearly  every  grape-growing  county  of  the  State. 


136  UNIVERSITY  OF  CALIFORNIA — EXPERIMENT   STATION. 

Methods  of  Treatment. — Since  sulfuring  the  vines  for  the  treatment  of 
oidium  has  become  general  in  France,  there  has  been  little  trouble  with 
erinose.  The  mite  seems  as  sensitive  to  the  fumes  of  sulfur  as  the  red 
spider,  and  several  sulfurings  during  the  late  spring  and  early  summer 
are  recommended  for  the  control  of  the  mite.  The  only  vineyards  which 
have  been  found  badly  affected  in  California  are  those  in  which  little  or  no 
sulfuring  has  been  done,  or  those  where  the  growth  of  foliage  has  been 
so  luxuriant  as  to  prevent  the  evaporation  of  the  sulfur  by  the  sun. 
In  the  latter  cases  the  vines  are  so  strong  that  they  practically 
receive  no  harm  from  the  disease.  Tests  made  on  Tokay  vines  indicate 
that  the  erinose  can  be  easily  and  readily  controlled  at  any  stage  in 
California  by  sulfuring.  In  severe  cases  a  winter  treatment  of  the  vine 
stumps  is  practiced  in  France.  This  treatment  consists  in  pouring 
about  one  quart  of  boiling  water  over  the  stump.  For  very  large 
stumps  a  somewhat  greater  amount  of  water  is  used,  and  for  smaller 
vines  a  proportionate  amount.  This  method  is  said  to  be  very  efficacious, 
and  with  the  portable  boiler  constructed  for  the  purpose  two  men  can 
treat  from  fifteen  hundred  to  two  thousand  vines  per  day.  Cuttings 
taken  from  affected  vines  for  the  purpose  of  rooting  or  grafting  may  be 
thoroughly  disinfected  by  placing  them  in  hot  water  (122°  F.)  for  ten 
minutes.  If  this  is  done  carefully  all  the  mites  and  their  eggs  will  be 
destroyed  without  injury  to  the  cuttings. 


NEMATODE  ROOT  GALL. 

(Heterodera  radicola  (Greef)  Mull.) 

Nematodes  are  not  insects,  nor  are  they  very  closely  related  to 
insects.  They  belong  to  the  class  of  animals  known  as  Vermes  or  true 
worms.  The  common  earthworm  is  the  best  known  example  of  the 
class,  although  it  occupies  a  position  in  the  group  higher  than  that  of 
the  nematodes.  There  are  a  good  many  species  of  nematodes — some 
living  in  the  ground,  a  good  many  are  parasites  on  animals,  and  a  few 
live  parasitically  on  plants.  Often  in  moist  soil,  rich  in  humus,  such  as 
vegetable  gardens,  there  may  be  large  numbers  of  very  minute  whitish 
transparent  worms.  These  are  nematodes,  however,  that  do  no  notice- 
able injury  to  plants,  and  it  is  only  the  parasitic  species,  of  which  the 
subject  of  this  account  is  an  example,  that  are  of  any  concern  to  growers 
of  crops. 

The  specie-  of  nematode  worm  that  attacks  the  grapevine  in  this 
State  -according  to  Dr.  Ernst  Bessey  of  the  Department  of  Agricul- 
ture, who  is;  at  present  engaged  in  an  investigation  of  this  group— is 
Heterodera   radicola  (Greef)  Mull.     This  species  is  widely  distributed 


BULLETIN    192. 


INSECTS    INJURIOUS   TO   THE   VINE. 


137 


over  the  world,  and  attacks  a  large  variety  of  plants.  In  the  Argentine 
Republic  it  is  said  to  be  the  most  destructive  disease  of  the  vine  occur- 
ring in  that  country.*  In  the  United  States,  outside  of  greenhouses, 
nematodes  are  chiefly  injurious  in  the  Southern  States  and  in  California. 

This  parasitic  species  is  an  exceedingly  small  wormlike  creature 
about  one  seventy-fifth  of  an  inch  long,  and  of  a  transparent  whitish 
color.  It  has  a  sharp  slender  organ  on  the  head  that  enables  it  to  make 
its  way  into  the  more  tender  portions  of  the  roots,  where  it  embeds  itself 
in  the  tissues.  Here  it  develops,  and  lays  the  eggs  from  which  succeed- 
ing generations  arise.  These  may  scatter  through  the  soil  and  attack 
other  portions  of  the  root.  By  means  of 
this  sharp  lancelike  organ  they  are  able  to 
draw  nourishment  from  the  roots.  It  is  not  M  Jf% 
so  much  this  direct  drain  on  the  roots,  how- 
ever, that  causes  the  damage  as  it  is  in  the 
decay  of  the  hypertrophied  tissue  due  to  the 
irritation  caused  by  the  work  of  the  worms. 
They  make  conditions  favorable  for  the 
attack  of  wood-rot  fungi,  which  hasten  the 
decay.  The  roots  of  vines  infested  with 
this  worm  show  numerous  swellings,  some- 
what like  that  due  to  phylloxera.  The 
nodosities  or  swellings  caused  by  phyllox- 
era, however,  are  most  conspicuous  and  are 
larger  on  the  smaller  roots,  while  those  of 
nematodes  are  largest  on  the  larger  roots. 
The  swellings  are  also  of  firmer  consistency 
than  those  of  phylloxera. 

The  general  effect  on  the  vine  is  not  very  different  from  that  of  the 
phylloxera.  The  distribution  of  the  affected  vines  will,  however,  gener- 
ally distinguish  the  two.  Vineyards  infested  with  phylloxera  show  the 
characteristic  oil-spots,  the  interior  vines  being  worst  affected  and  grad- 
ually diminishing  in  injury  toward  the  periphery  of  the  affected  spot. 
The  amount  of  injury  is  said  to  vary  with  the  soil  conditions,  but  the 
authorities  apparently  are  not  agreed,  some  claiming  less  injury  in 
light,  sandy  soil  and  others  the  reverse.  Moisture  is,  no  doubt,  the 
most  important  factor  in  favoring  their  development.  In  California 
this  pest  seems  to  be  most  common  on  vines  in  the  Fresno  section,  and, 
in  general,  this  is  a  section  of  sandy  soil. 

Control. — No  satisfactory  remedy  has  yet  been  found  for  controlling 
parasitic  nematodes.  In  greenhouses  the  usual  procedure  is  to  sterilize 
the  soil,  but  this,  obviously,  is  not  applicable  to  a  vineyard.     However, 


FIG.  24.  N.  Swellings  on  the  roots 
of  vine  caused  by  the  Nematode 
root  gall.  M,  M.  Eggs  of  the 
Nematodes  found  in  these  galls. 


*Boletin  del  Ministerio  de  Agricultura,  Buenos  Ayres,  Mayo  de  1906. 


13S  UNIVERSITY  OF   CALIFORNIA EXPERIMENT   STATION. 

if  the  soil  is  known  to  be  infested,  disinfection  is  sometimes  practiced 
before  planting  out  young  vines.  This  is  done  by  an  application  of 
carbon  bisulfid  to  the  soil.  Trap  plants  have  also  been  used,  these  being 
annuals  that  are  pulled  up  before  the  nematodes  escape.  In  time  it 
may  be  found  that  resistant  stock  is  the  solution  of  the  problem.  In 
the  bulletin  already  referred  to  it  is  stated  that  the  Isabella  is  slightly 
resistant,  while  Vitis  riparia  has  shown  no  nodules  after  the  first  year. 
This  fact  is  interesting  as  a  suggestion  that  both  phylloxera  and 
nematodes  may  be  controlled  by  the  same  resistant. 


Bulletin  192.  INSECTS  INJURIOUS  TO  THE  VINE.  139 


KEY  FOR  DETERMINING  THE   INSECT  INJURIES  TO  THE  VINE 
DESCRIBED  IN  THIS  BULLETIN. 


Injury  to  the  Leaves. 

No  part  of  the  leaf  eaten  away,  but  having  pale  spots,  or  being 
entirely  pale  yellow,  or  dried  up,  those  about  the  crown  of  the  vine, 
particularly  the  lower  ones,  worst  affected.      Vine  hopper,  page  111. 

Leaves  with  irregular  holes  eaten  out.  Flea  beetles,  page  128;  Grass- 
hoppers, page  122;  or  Leaf  chafers,  page  132. 

Leaves  with  regular  chain-like  slits  eaten  away.    Root  beetles,  page  116. 

Leaves  rolled  up  from  one  side.     Leaf  rollers,  page  129. 

Leaves  entirely  devoured.  Army  worms,  page  124;  Grasshoppers , 
page  122;  Hawk  moth  larvse,  page  119. 

Leaves  with  swellings  on  upper  surface,  and  grayish  white  to  dark, 
brown  felt  covering  on  corresponding  depressions  on  under  side.  Erinose, 
page  134. 

Injury  to  Petioles  and  Pedicels. 

Narrow  strips  of  uniform  size  eaten  away.     Root  beetle,  page  116. 

Injury  to  the  Berry. 

Narrow  strips  about  one  fourth  of  an  inch  long  gouged  out.  Root 
beetle,  page  116. 

Clusters  cut  off  and  dropped  to  ground.     Army  worm,  page  124. 

Injury  to  the  Roots. 

Long  strips  of  the  bark  eaten  away.     Root  beetle,  page  116. 

The  smaller  rootlets  only  eaten  off'.     Wire  worm,  page  133. 

Nodosities  or  swellings,  largest  on  smaller  roots,  often  at  extreme  tip, 
decay  of  hypertrophied  tissue.     Phylloxera,  page  99. 

Nodosities  or  swellings  largest  on  larger  roots,  two  or  three  times  the 
diameter  of  those  caused  by  phylloxera,  and  of  firmer  consistency, 
none  at  extreme  tip.     Nematodes,  page  136. 

Injury  to  the  Whole  Vine. 

These  are  the  same  as  under  root  injury,  since  injury  to  the  roots 
affects  the  vine  as  a  whole. 

Vines  whose  canes  are  checked  in  growth  or  completely  stunted,  and 
if  leaves  have  chain-like  strips  eaten  out.     Root  worm,  page  116. 


140  UNIVERSITY  OF   CALIFORNIA EXPERIMENT   STATION. 

Vines  in  circular  spots  in  vineyard  showing  stunted  growth,  those 
in  center  of  spot  worst  affected  and  gradually  diminishing  outward. 
Phylloxera,  page  99. 

Vines  with  symptoms  similar  to  phylloxera,  but  not  in  well-defined 
circular  spots,  nor  with  interior  ones  worst  affected.    Nematodes,  page  136. 


HOW  TO  SEND  SPECIMENS. 

Insect  specimens  should  be  inclosed  in  a  wooden,  tin  or  strong  paste- 
board box.  No  provision  need  be  made  for  air.  Accompany  specimens 
with  samples  of  their  work.  If  roots  or  leaves,  wrap  in  moist  news- 
paper and  inclose  in  tight  box  to  prevent  drying.  If  phylloxera  is 
suspected,  place  pieces  of  roots  in  a  firm  box  that  is  absolutely  tight; 
or  otherwise  thoroughly  seal,  to  prevent  any  possibility  of  escape  in  the 
mails. 


STATION   PUBLICATIONS. 


STATION  PUBLICATIONS  AVAILABLE  FOR  DISTRIBUTION. 


REPORTS. 


1896.  Report   of    the    Viticultural    Work    during    the   seasons    1887-93,    with   data 

regarding  the  Vintages  of  1894-95. 

1897.  Resistant    Vines,    their    Selection,    Adaptation,    and    Grafting.      Appendix    to 

Viticultural  Report  for  1896. 

1898.  Partial   Report  of  Work  of  Agricultural   Experiment  Station   for  the  years 

1895-96  and  1896-97. 
1900.     Report  of  the  Agricultural  Experiment  Station  for  the  year  1897-98. 

1902.  Report  of  the  Agricultural  Experiment  Station  for  1898-1901. 

1903.  Report  of  the  Agricultural  Experiment  Station  for  1901-1903. 

1904.  Twenty-second  Report  of  the  Agricultural  Experiment  Station  for  1903-1904- 

TECHNICAL   BULLETINS— ENTOMOLOGICAL  SERIES. 

Vol.  1,  No.  1 — Wing  Veins  of  Insects. 

No.  2 — Catalogue  of  the  Ephydridse. 

BULLETINS. 

Reprint.  Endurance  of  Drought  in  Soils  of  the  Arid  Region. 

No.  128.  Nature,  Value  and  Utilization  of  Alkali  Lands,  and  Tolerance  of  Alkali. 
(Revised  and  Reprint,  1905.) 

133.  Tolerance  of  Alkali  by  Various  Cultures. 

140.  Lands  of  the  Colorado  Delta  in  Salton  Basin,  and  Supplement. 

141.  Deciduous  Fruits  at  Paso  Robles. 

142.  Grasshoppers  in  California. 

147.  Culture  Work  of  the  Substations. 

148.  Resistant  Vines  and  their  Hybrids. 

149.  California  Sugar  Industry. 

150.  The  Value  of  Oak  Leaves  for  Forage. 

151.  Arsenical  Insecticides. 

152.  Fumigation  Dosage. 

153.  Spraying  with  Distillates. 

154.  Sulfur  Sprays  for  Red  Spider. 
156.  Fowl  Cholera. 

158.  California  Olive  Oil ;  its  Manufacture. 

159.  Contribution  to  the  Study  of  Fermentation. 

160.  The  Hop  Aphis. 

161.  Tuberculosis  in  Fowls.      (Reprint.) 

162.  Commercial  Fertilizers.      (Dec.  1,  1904.) 

163.  Pear  Scab. 

164.  Poultry  Feeding  and  Proprietary  Foods.      (Reprint.) 

165.  Asparagus  and  Asparagus  Rust  in  California. 

166.  Spraying  for  Scale  Insects. 

167.  Manufacture  of  Dry  Wines  in  Hot  Countries. 

168.  Observations  on  Some  Vine  Diseases  in  Sonoma  County. 

169.  Tolerance  of  the  Sugar  Beet  for  Alkali. 

170.  Studies  in  Grasshopper  Control. 

171.  Commercial  Fertilizers.      (June  30,  1905.) 

172.  Further  Experience  in  Asparagus  Rust  Control. 

173.  Commercial  Fertilizers.      (December,  1905.) 

174.  A  New  Wine-Cooling  Machine. 

175.  Tomato  Diseases  in  California. 

176.  Sugar  Beets  in  the  San  Joaquin  Valley. 

177.  A  New  Method  of  Making  Dry  Red  Wine. 

178.  Mosquito  Control. 

179.  Commercial  Fertilizers.     (June,  1906.) 

180.  Resistant  Vineyards. 

181.  The  Selection  of  Seed-Wheat. 

182.  Analysis  of  Paris  Green  and  Lead  Arsenate.     Proposed  Insecticide  Law. 

183.  The  California  Tussock-moth. 

184.  Report  of  the  Plant  Pathologist  to  July  1,  1906. 

185.  Report  of  Progress  in  Cereal  Investigations. 

186.  The  Oidium  of  the  Vine. 

187.  Commercial   Fertilizers.      (January,   1907.) 

188.  Lining  of  Ditches  and  Reservoirs  to  Prevent  Seepage  and  Losses. 

189.  Commercial  Fertilizers.     (June,  1907.) 

190.  The  Brown  Rot  of  the  Lemon. 

191.  California  Peach  Blight. 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 


CIRCULARS. 


No.  1. 
2 

3.' 
4. 
5. 
7. 
9. 
10. 

11. 
12. 
13. 
15. 

16. 
17. 

18. 
19. 
20. 
21. 

22. 


Texas  Fever. 

Blackleg. 

Hog  Cholera. 

Anthrax. 

Contagious  Abortion  in  Cows. 

Remedies  for  Insects. 

Asparagus  Rust. 

Reading  Course  in  Economic 

Entomology.      ( Revision. ) 
Fumigation  Practice. 
Silk  Culture. 

The  Culture  of  the   Sugar  Beet. 
Recent   Problems   in   Agriculture. 

What  a  University  Farm  is  For. 
Notes  on  Seed-Wheat. 
Why      Agriculture      Should      Be 

Taught  in  the  Public  Schools. 
Caterpillars  on  Oaks. 
Disinfection   of   Stables. 
Reading  Course  in  Irrigation. 
The  Advancement  of  Agricultural 

Education. 
Defecation    of    Must    for    White 

Wine. 


No.  23. 
24. 
25. 

26. 

27. 


28. 


29. 


30. 
31. 


32. 
33. 


Pure  Yeast  in  Wineries. 

Olive  Pickling. 

Suggestions  Regarding  Exam- 
ination of  Lands. 

Selection  and  Preparation  of 
Vine  Cuttings. 

Marly  Subsoils  and  the  Chlo- 
rosis or  Yellowing  of  Citrus 
Trees. 

A  Preliminary  Progress  Report 
of  Cereal  Investigations,  1905- 
1907. 

Preliminary  Announcement  con- 
cerning Instruction  in  Practi- 
cal Agriculture  upon  the 
University  Farm,  Davisville, 
Cal. 

White  Fly  in  California. 

The  Agricultural  College  and  Its 
Relationship  to  the  Scheme  of 
National    Education. 

White  Fly  Eradication. 

Packing  Prunes  in  Cans.  Cane 
Sugar  vs.   Beet  Sugar. 


Copies  may  be  had  on  application  to  Director  of  Experiment  Station,  Berkeley,  CaL 


